diff --git a/src/lib.rs b/src/lib.rs
index 4bc6a33a..55c4a9b8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -826,14 +826,14 @@ impl CertificateParams {
 			serial_number,
 			subject_alt_names: _,
 			distinguished_name,
-			is_ca,
-			key_usages,
-			extended_key_usages,
-			name_constraints,
-			crl_distribution_points,
+			is_ca: _,
+			key_usages: _,
+			extended_key_usages: _,
+			name_constraints: _,
+			crl_distribution_points: _,
 			custom_extensions: _,
 			key_pair,
-			use_authority_key_identifier_extension,
+			use_authority_key_identifier_extension: _,
 			key_identifier_method,
 		} = self;
 		// - alg and key_pair will be used by the caller
@@ -843,14 +843,7 @@ impl CertificateParams {
 		// from the defaults so this is left for a later version if
 		// needed.
 		let _ = (alg, key_pair, not_before, not_after, key_identifier_method);
-		if serial_number.is_some()
-			|| *is_ca != IsCa::NoCa
-			|| !key_usages.is_empty()
-			|| !extended_key_usages.is_empty()
-			|| name_constraints.is_some()
-			|| !crl_distribution_points.is_empty()
-			|| *use_authority_key_identifier_extension
-		{
+		if serial_number.is_some() {
 			return Err(RcgenError::UnsupportedInCsr);
 		}
 		writer.write_sequence(|writer| {
diff --git a/tests/generic.rs b/tests/generic.rs
index 2b158c7c..08dd02b5 100644
--- a/tests/generic.rs
+++ b/tests/generic.rs
@@ -84,6 +84,249 @@ mod test_convert_x509_subject_alternative_name {
 	}
 }
 
+#[cfg(feature = "x509-parser")]
+mod test_csr_exts {
+	use crate::util;
+	use rcgen::{
+		BasicConstraints, Certificate, CrlDistributionPoint, GeneralSubtree, KeyUsagePurpose,
+		SanType,
+	};
+	use x509_parser::prelude::{
+		FromDer, ParsedExtension, X509Certificate, X509CertificationRequest,
+	};
+
+	#[test]
+	fn test_rcgen_extensions() {
+		// Create a certificate that has several rcgen managed extensions (e.g. not custom extensions).
+		let mut params = util::default_params();
+		params.subject_alt_names = vec![SanType::DnsName("san.example.com".into())];
+		let path_len_constraint = 3;
+		params.is_ca = rcgen::IsCa::Ca(BasicConstraints::Constrained(path_len_constraint));
+		params.key_usages = vec![
+			KeyUsagePurpose::DigitalSignature,
+			KeyUsagePurpose::KeyEncipherment,
+		];
+		params.extended_key_usages = vec![
+			rcgen::ExtendedKeyUsagePurpose::ServerAuth,
+			rcgen::ExtendedKeyUsagePurpose::ClientAuth,
+		];
+		params.name_constraints = Some(rcgen::NameConstraints {
+			permitted_subtrees: vec![GeneralSubtree::DnsName("example.com".into())],
+			excluded_subtrees: vec![GeneralSubtree::DnsName("example.org".into())],
+		});
+		params.crl_distribution_points = vec![CrlDistributionPoint {
+			uris: vec!["http://example.com".into()],
+		}];
+		let test_cert = Certificate::from_params(params).unwrap();
+		let test_cert_der = test_cert.serialize_der().unwrap();
+
+		// We should be able to parse it and find the expected extensions present.
+		let (_, x509_test_cert) = X509Certificate::from_der(&test_cert_der).unwrap();
+
+		// Check SAN is present, not critical, and not empty.
+		let san_ext = x509_test_cert
+			.subject_alternative_name()
+			.expect("invalid SAN ext")
+			.expect("missing SAN ext");
+		assert!(!san_ext.critical);
+		assert!(!san_ext.value.general_names.is_empty());
+
+		// Check basic constraints are present, critical, and have the expected path len constraint.
+		let basic_constraints = x509_test_cert
+			.basic_constraints()
+			.expect("invalid basic constraints")
+			.expect("missing basic constraints");
+		assert!(basic_constraints.critical);
+		let assert_basic_constraints =
+			|basic_constraints: &x509_parser::prelude::BasicConstraints| {
+				assert!(basic_constraints.ca);
+				assert_eq!(
+					basic_constraints
+						.path_len_constraint
+						.expect("missing path len constraint"),
+					path_len_constraint as u32
+				);
+			};
+		assert_basic_constraints(basic_constraints.value);
+
+		// Check name constraints are present, critical and non-empty.
+		let name_constraints = x509_test_cert
+			.name_constraints()
+			.expect("invalid name constraints")
+			.expect("missing name constraints");
+		assert!(name_constraints.critical);
+		let assert_name_constraints = |name_constraints: &x509_parser::prelude::NameConstraints| {
+			assert!(!name_constraints
+				.permitted_subtrees
+				.clone()
+				.expect("missing permitted subtrees")
+				.is_empty());
+			assert!(!name_constraints
+				.excluded_subtrees
+				.clone()
+				.expect("missing excluded subtrees")
+				.is_empty());
+		};
+		assert_name_constraints(name_constraints.value);
+
+		// Check CRL distribution point is present and non-critical.
+		let crl_distrib_point = x509_test_cert
+			.get_extension_unique(&x509_parser::oid_registry::OID_X509_EXT_CRL_DISTRIBUTION_POINTS)
+			.expect("malformed CRL distribution points extension")
+			.expect("missing CRL distribution points extension");
+		assert!(!crl_distrib_point.critical);
+		// See parse_crl_dps for a test of the ext structure/value.
+
+		// Check key usage is present, and critical.
+		let key_usage = x509_test_cert
+			.key_usage()
+			.expect("invalid key usage")
+			.expect("missing key usage");
+		assert!(key_usage.critical);
+
+		// Check extended key usage is present, and non-critical.
+		let extended_key_usage = x509_test_cert
+			.extended_key_usage()
+			.expect("invalid extended key usage")
+			.expect("missing extended key usage");
+		assert!(!extended_key_usage.critical);
+
+		// Check subject key identifier is present, non-critical, and matches the expected value.
+		let ski = x509_test_cert
+			.get_extension_unique(&x509_parser::oid_registry::OID_X509_EXT_SUBJECT_KEY_IDENTIFIER)
+			.expect("invalid SKI extension")
+			.expect("missing SKI extension");
+		assert!(!ski.critical);
+		let ski = match ski.parsed_extension() {
+			ParsedExtension::SubjectKeyIdentifier(key_id) => key_id,
+			_ => panic!("unexpected parsed extension type"),
+		};
+		assert_eq!(ski.0, &test_cert.get_key_identifier());
+
+		let aki = x509_test_cert
+			.get_extension_unique(&x509_parser::oid_registry::OID_X509_EXT_AUTHORITY_KEY_IDENTIFIER)
+			.expect("invalid AKI extension")
+			.expect("missing AKI extension");
+		assert!(!aki.critical);
+		let aki = match aki.parsed_extension() {
+			ParsedExtension::AuthorityKeyIdentifier(key_id) => key_id,
+			_ => panic!("unexpected parsed extension type"),
+		};
+		assert_eq!(
+			aki.key_identifier
+				.clone()
+				.expect("missing key identifier")
+				.0,
+			&test_cert.get_key_identifier()
+		);
+
+		// Generate a CSR from our cert, parse it with x509-parser.
+		let test_cert_csr_der = test_cert.serialize_request_der();
+		let test_cert_csr_der = test_cert_csr_der.unwrap();
+		let (_, x509_csr) = X509CertificationRequest::from_der(&test_cert_csr_der).unwrap();
+
+		let parsed_exts = x509_csr
+			.requested_extensions()
+			.expect("missing CSR requested extensions")
+			.collect::<Vec<_>>();
+
+		// The basic constraints we specified should be there.
+		let basic_constraints = parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::BasicConstraints(bc) = ext {
+					Some(bc)
+				} else {
+					None
+				}
+			})
+			.expect("missing basic constraints");
+		assert_basic_constraints(basic_constraints);
+
+		let ski = parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::SubjectKeyIdentifier(ski) = ext {
+					Some(ski)
+				} else {
+					None
+				}
+			})
+			.expect("missing subject key identifier");
+		assert_eq!(ski.0, &test_cert.get_key_identifier());
+
+		parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::CRLDistributionPoints(ski) = ext {
+					Some(ski)
+				} else {
+					None
+				}
+			})
+			.expect("missing CRL distribution points");
+
+		let name_constraints = parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::NameConstraints(name_constraints) = ext {
+					Some(name_constraints)
+				} else {
+					None
+				}
+			})
+			.expect("missing name constraints");
+		assert_name_constraints(name_constraints);
+
+		parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::ExtendedKeyUsage(eku) = ext {
+					Some(eku)
+				} else {
+					None
+				}
+			})
+			.expect("missing extended key usage");
+
+		parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::KeyUsage(ku) = ext {
+					Some(ku)
+				} else {
+					None
+				}
+			})
+			.expect("missing key usage");
+
+		parsed_exts
+			.iter()
+			.find_map(|ext| {
+				if let ParsedExtension::SubjectAlternativeName(san) = ext {
+					Some(san)
+				} else {
+					None
+				}
+			})
+			.expect("missing subject alternative name");
+
+		// We should not find the AKI extension in the CSR. That's provided by an issuer
+		// when issuing the certificate (e.g. as we did above w/ serialize_der making a
+		// self signed cert that contained an AKI).
+		assert_eq!(
+			parsed_exts.iter().find_map(|ext| {
+				if let ParsedExtension::AuthorityKeyIdentifier(aki) = ext {
+					Some(aki)
+				} else {
+					None
+				}
+			}),
+			None
+		);
+	}
+}
+
 #[cfg(feature = "x509-parser")]
 mod test_x509_custom_ext {
 	use crate::util;