diff --git a/src/Unrolled.jl b/src/Unrolled.jl
index 2f9afc0..1c62ca9 100644
--- a/src/Unrolled.jl
+++ b/src/Unrolled.jl
@@ -14,6 +14,12 @@ function unrolled_filter end
 for sequence-like types, obviously. """
 function type_length end
 
+"""
+`type_size(::Type, dim)` returns the size of an array in the specified dimension.
+"""
+function type_size end
+
+
 include("range.jl")
 
 const expansion_funs = Dict{Function, Function}()
@@ -52,6 +58,7 @@ end
 type_length(tup::Type{T}) where {T<:Tuple} = length(tup.parameters)
 # Default fall-back
 type_length(typ::Type) = length(typ)
+type_size(typ::Type, i) = size(typ, i)
 
 """ `function_argument_name(arg_expr)`
 
@@ -80,6 +87,13 @@ macro unroll(fundef)
                 "Can only unroll a loop over one of the function's arguments")
         return Expr(:($), Expr(:call, :($Unrolled.type_length), seq_var))
     end
+    function seq_type_size(seq_var, dim)
+        @assert(seq_var in all_args,
+                "Can only unroll a loop over one of the function's arguments")
+        @assert(dim isa Integer,
+                "Dimension argument must be an integer")
+        return Expr(:($), Expr(:call, :($Unrolled.type_size), seq_var, dim))
+    end
     process(x) = x
     function process(expr::Expr)
         if expr.args[1]==Symbol("@unroll")
@@ -88,6 +102,9 @@ macro unroll(fundef)
                 for var_ in 1:length(seq_) loopbody__ end =>
                     :($Unrolled.@unroll_loop(for $var in 1:$(seq_type_length(seq));
                                              $(loopbody...) end))
+                for var_ in 1:size(seq_, dim_) loopbody__ end =>
+                    :($Unrolled.@unroll_loop(for $var in 1:$(seq_type_size(seq, dim));
+                                          $(loopbody...) end))
                 for var_ in seq_ loopbody__ end =>
                     :($Unrolled.@unroll_loop($(seq_type(seq)),
                                              for $var in $seq; $(loopbody...) end))
diff --git a/test/runtests.jl b/test/runtests.jl
index 5effcd1..bfd09f9 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -106,3 +106,18 @@ end
     end
     return log_scale ? exp.(state) : state
 end
+
+# Unrolling with a sized argument
+struct CartesianIndexSpace{dims} <: AbstractArray{Int, 2}; end
+Base.size(cis::Type{CartesianIndexSpace{dims}}) where {dims} = dims
+Base.size(cis::Type{<:CartesianIndexSpace}, i::Integer) = size(cis)[i]
+Base.size(cis::CartesianIndexSpace) = size(typeof(cis))
+
+@unroll function do_count(cis)
+    n = 0
+    @unroll for i = 1:size(cis, 2)
+        n += 1
+    end
+    n
+end
+@test do_count(CartesianIndexSpace{(1,4)}()) == 4