diff --git a/Project.toml b/Project.toml
index 057ee785a..570a25c05 100644
--- a/Project.toml
+++ b/Project.toml
@@ -11,17 +11,20 @@ RoundingEmulator = "5eaf0fd0-dfba-4ccb-bf02-d820a40db705"
 [weakdeps]
 DiffRules = "b552c78f-8df3-52c6-915a-8e097449b14b"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
 
 [extensions]
 IntervalArithmeticDiffRulesExt = "DiffRules"
 IntervalArithmeticForwardDiffExt = "ForwardDiff"
+IntervalArithmeticsIntervalSetsExt = "IntervalSets"
 IntervalArithmeticRecipesBaseExt = "RecipesBase"
 
 [compat]
 CRlibm_jll = "1"
 DiffRules = "1"
 ForwardDiff = "0.10"
+IntervalSets = "0.7"
 MacroTools = "0.5"
 RecipesBase = "1"
 RoundingEmulator = "0.2"
diff --git a/ext/IntervalArithmeticsIntervalSetsExt.jl b/ext/IntervalArithmeticsIntervalSetsExt.jl
new file mode 100644
index 000000000..d5b89713e
--- /dev/null
+++ b/ext/IntervalArithmeticsIntervalSetsExt.jl
@@ -0,0 +1,23 @@
+module IntervalArithmeticsIntervalSetsExt
+
+import IntervalSets as IS
+import IntervalArithmetic as IA
+
+IA.interval(i::IS.Interval{L,R,T}) where {L,R,T} = IA.interval(IA.promote_numtype(T, T), i)
+function IA.interval(::Type{T}, i::IS.Interval{L,R}) where {T<:IA.NumTypes,L,R}
+    # infinite endpoints are always open in IA, finite always closed:
+    isinf(IS.leftendpoint(i)) != IS.isleftopen(i) && return IA.nai(T)
+    isinf(IS.rightendpoint(i)) != IS.isrightopen(i) && return IA.nai(T)
+    x = IA.interval(T, IS.endpoints(i)...)
+    return IA._unsafe_interval(IA.bareinterval(x), IA.decoration(x), false)
+end
+
+function IS.Interval(i::IA.Interval)
+    lo, hi = IA.bounds(i)
+    # infinite endpoints are always open in IA, finite always closed:
+    L = ifelse(isinf(lo), :open, :closed)
+    R = ifelse(isinf(hi), :open, :closed)
+    return IS.Interval{L,R}(lo, hi)
+end
+
+end
diff --git a/test/Project.toml b/test/Project.toml
index a7e449099..70dd3a83f 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -1,4 +1,5 @@
 [deps]
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
+IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
diff --git a/test/interval_tests/construction.jl b/test/interval_tests/construction.jl
index 4115a9e01..81e882302 100644
--- a/test/interval_tests/construction.jl
+++ b/test/interval_tests/construction.jl
@@ -157,6 +157,27 @@ end
     @test_throws DomainError convert(Interval{Float64}, interval(1+im))
 end
 
+@testset "Interval types conversion" begin
+    i = interval(IS.Interval(1, 2))
+    @test isequal_interval(i, interval(1., 2.)) && !isguaranteed(i)
+    i = interval(IS.Interval(0.1, 2))
+    @test isequal_interval(i, interval(0.1, 2.)) && !isguaranteed(i)
+    @test interval(Float64, IS.Interval(0.1, 2)) === i
+    
+    i = interval(IS.iv"[0.1, Inf)")
+    @test isequal_interval(i, interval(0.1, Inf)) && !isguaranteed(i)
+    @test interval(IS.iv"[0.1, Inf]") === nai(Float64)
+    @test interval(IS.iv"(0.1, Inf]") === nai(Float64)
+    @test interval(IS.iv"(0.1, Inf)") === nai(Float64)
+    @test interval(IS.iv"(0.1, 1)") === nai(Float64)
+    @test interval(IS.iv"(0.1, 1]") === nai(Float64)
+
+    @test IS.Interval(interval(1, 2)) === IS.Interval(1., 2.)
+    @test IS.Interval(interval(0.1, 2)) === IS.Interval(0.1, 2.)
+    @test IS.Interval(interval(0.1, Inf)) === IS.iv"[0.1, Inf)"
+    @test IS.Interval(interval(-Inf, Inf)) === IS.iv"(-Inf, Inf)"
+end
+
 @testset "Propagation of `isguaranteed`" begin
     @test !isguaranteed(interval(convert(Interval{Float64}, 0), interval(convert(Interval{Float64}, 1))))
     @test !isguaranteed(interval(0, convert(Interval{Float64}, 1)))
diff --git a/test/runtests.jl b/test/runtests.jl
index 1c5cf2d50..cebbfb63a 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -3,6 +3,7 @@ using Test
 using ForwardDiff
 using IntervalArithmetic
 using InteractiveUtils
+import IntervalSets as IS
 
 include("generate_ITF1788.jl")