diff --git a/Project.toml b/Project.toml
index 2a8303b..ae37e3b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "PooledArrays"
 uuid = "2dfb63ee-cc39-5dd5-95bd-886bf059d720"
-version = "1.3.0"
+version = "1.4.0"
 
 [deps]
 DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"
diff --git a/src/PooledArrays.jl b/src/PooledArrays.jl
index 5829085..c70bd36 100644
--- a/src/PooledArrays.jl
+++ b/src/PooledArrays.jl
@@ -590,11 +590,20 @@ end
 ##
 ##############################################################################
 
-function Base.push!(pv::PooledVector{S,R}, v::T) where {S,R,T}
+function Base.push!(pv::PooledVector, v) # this function is not thread safe
     push!(pv.refs, getpoolidx(pv, v))
     return pv
 end
 
+function Base.insert!(pv::PooledVector, i::Integer, v) # this function is not thread safe
+    i isa Bool && throw(ArgumentError("invalid index: $i of type Bool"))
+    if !(1 <= i <= length(pv.refs) + 1)
+        throw(BoundsError("attempt to insert to a vector with length $(length(pv)) at index $i"))
+    end
+    insert!(pv.refs, i, getpoolidx(pv, v))
+    return pv
+end
+
 function Base.append!(pv::PooledVector, items::AbstractArray)
     itemindices = eachindex(items)
     l = length(pv)
diff --git a/test/runtests.jl b/test/runtests.jl
index ee5f4cc..0a7a31d 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -569,3 +569,19 @@ end
         end
     end
 end
+
+@testset "insert! test" begin
+    x = PooledArray([1, 2, 3])
+    @test insert!(x, 2, 10) == [1, 10, 2, 3]
+    @test_throws ArgumentError insert!(x, true, 10)
+    @test_throws BoundsError insert!(x, 0, 10)
+    @test x == [1, 10, 2, 3]
+    @test x.pool == [1, 2, 3, 10]
+    @test insert!(x, 3, 'c') == [1, 10, 99, 2, 3]
+    @test x.pool == [1, 2, 3, 10, 99]
+    @test insert!(x, 1, true) == [1, 1, 10, 99, 2, 3]
+    @test x.pool == [1, 2, 3, 10, 99]
+    @test insert!(x, 7, true) == [1, 1, 10, 99, 2, 3, 1]
+    @test_throws BoundsError insert!(x, 9, true)
+    @test x == [1, 1, 10, 99, 2, 3, 1]
+end