diff --git a/REQUIRE b/REQUIRE
index b213ed1..7edcc3b 100644
--- a/REQUIRE
+++ b/REQUIRE
@@ -1,2 +1,2 @@
 julia 0.6
-Nulls
+Missings
diff --git a/src/WeakRefStrings.jl b/src/WeakRefStrings.jl
index f9d9900..4030a14 100644
--- a/src/WeakRefStrings.jl
+++ b/src/WeakRefStrings.jl
@@ -3,7 +3,7 @@ module WeakRefStrings
 
 export WeakRefString, WeakRefStringArray
 
-using Nulls
+using Missings
 
 """
 A custom "weakref" string type that only points to external string data.
@@ -81,24 +81,24 @@ struct WeakRefStringArray{T, N} <: AbstractArray{T, N}
 end
 
 WeakRefStringArray(data::Vector{UInt8}, ::Type{T}, rows::Integer) where {T <: WeakRefString} = WeakRefStringArray(Any[data], zeros(T, rows))
-WeakRefStringArray(data::Vector{UInt8}, ::Type{Union{Null, T}}, rows::Integer) where {T} = WeakRefStringArray(Any[data], Vector{Union{Null, T}}(rows))
-WeakRefStringArray(data::Vector{UInt8}, A::Array{T}) where {T <: Union{WeakRefString, Null}} = WeakRefStringArray(Any[data], A)
+WeakRefStringArray(data::Vector{UInt8}, ::Type{Union{Missing, T}}, rows::Integer) where {T} = WeakRefStringArray(Any[data], Vector{Union{Missing, T}}(rows))
+WeakRefStringArray(data::Vector{UInt8}, A::Array{T}) where {T <: Union{WeakRefString, Missing}} = WeakRefStringArray(Any[data], A)
 
 wk(w::WeakRefString) = string(w)
-wk(::Null) = null
+wk(::Missing) = missing
 
 Base.size(A::WeakRefStringArray) = size(A.elements)
 Base.getindex(A::WeakRefStringArray, i::Int) = wk(A.elements[i])
 Base.getindex(A::WeakRefStringArray{T, N}, I::Vararg{Int, N}) where {T, N} = wk.(A.elements[I...])
-Base.setindex!(A::WeakRefStringArray{T, N}, v::Null, i::Int) where {T, N} = setindex!(A.elements, v, i)
-Base.setindex!(A::WeakRefStringArray{T, N}, v::Null, I::Vararg{Int, N}) where {T, N} = setindex!(A.elements, v, I...)
+Base.setindex!(A::WeakRefStringArray{T, N}, v::Missing, i::Int) where {T, N} = setindex!(A.elements, v, i)
+Base.setindex!(A::WeakRefStringArray{T, N}, v::Missing, I::Vararg{Int, N}) where {T, N} = setindex!(A.elements, v, I...)
 Base.setindex!(A::WeakRefStringArray{T, N}, v::WeakRefString, i::Int) where {T, N} = setindex!(A.elements, v, i)
 Base.setindex!(A::WeakRefStringArray{T, N}, v::WeakRefString, I::Vararg{Int, N}) where {T, N} = setindex!(A.elements, v, I...)
 Base.setindex!(A::WeakRefStringArray{T, N}, v::String, i::Int) where {T, N} = (push!(A.data, Vector{UInt8}(v)); setindex!(A.elements, v, i))
 Base.setindex!(A::WeakRefStringArray{T, N}, v::String, I::Vararg{Int, N}) where {T, N} = (push!(A.data, Vector{UInt8}(v)); setindex!(A.elements, v, I...))
 Base.resize!(A::WeakRefStringArray, i) = resize!(A.elements, i)
 
-Base.push!(a::WeakRefStringArray{T, 1}, v::Null) where {T} = (push!(a.elements, v); a)
+Base.push!(a::WeakRefStringArray{T, 1}, v::Missing) where {T} = (push!(a.elements, v); a)
 Base.push!(a::WeakRefStringArray{T, 1}, v::WeakRefString) where {T} = (push!(a.elements, v); a)
 function Base.push!(A::WeakRefStringArray{T, 1}, v::String) where T
     push!(A.data, Vector{UInt8}(v))
diff --git a/test/runtests.jl b/test/runtests.jl
index 5c9cb4c..52caa04 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,4 +1,4 @@
-using WeakRefStrings, Base.Test, Nulls
+using WeakRefStrings, Base.Test, Missings
 
 @testset "WeakRefString{UInt8}" begin
     data = Vector{UInt8}("hey there sailor")
@@ -73,13 +73,13 @@ end
     append!(A, B)
     @test size(A) == (17,)
 
-    D = WeakRefStringArray(UInt8[], Union{Null, WeakRefString{UInt8}}, 0)
+    D = WeakRefStringArray(UInt8[], Union{Missing, WeakRefString{UInt8}}, 0)
     push!(D, "hey")
     push!(D, str)
-    push!(D, null)
+    push!(D, missing)
     @test length(D) == 3
     @test D[2] == str
-    @test D[3] === null
-    D[2] = null
-    @test D[2] === null
+    @test D[3] === missing
+    D[2] = missing
+    @test D[2] === missing
 end