diff --git a/src/polynomial.jl b/src/polynomial.jl
index 879cfcf..55d2c4e 100644
--- a/src/polynomial.jl
+++ b/src/polynomial.jl
@@ -66,6 +66,8 @@ function Base.isequal(p::Polynomial{B}, q::Polynomial{B}) where {B}
     return isequal(p.monomial, q.monomial)
 end
 
+Base.isone(p::Polynomial) = isone(p.monomial)
+
 # Needed for `BoundsError`
 Base.iterate(p::Polynomial) = p, nothing
 Base.iterate(::Polynomial, ::Nothing) = nothing
diff --git a/test/monomial.jl b/test/monomial.jl
index 2f55d4f..24e569e 100644
--- a/test/monomial.jl
+++ b/test/monomial.jl
@@ -7,11 +7,14 @@ using DynamicPolynomials
 @testset "StarAlgebras" begin
     @polyvar x
     a = MB.Polynomial{MB.Monomial}(x)
+    @test !isone(a)
     b = a * a
     @test b.coeffs == sparse_coefficients(x^2)
     @test typeof(b.coeffs) == typeof(sparse_coefficients(x^2))
     @test MB.Polynomial{MB.Monomial}(x^2) == MB.Polynomial{MB.Monomial}(x^2)
     @test MB.Polynomial{MB.Monomial}(x^3) != MB.Polynomial{MB.Monomial}(x^2)
+    o = MB.Polynomial{MB.Monomial}(constant_monomial(x^2))
+    @test isone(o)
 end
 
 @testset "Linear" begin