diff --git a/src/diff.jl b/src/diff.jl
index 53122df..115df0e 100644
--- a/src/diff.jl
+++ b/src/diff.jl
@@ -26,3 +26,32 @@ function MP.differentiate(p::Polynomial{C, T}, x::PolyVar{C}) where {C, T}
         Polynomial(a, MonomialVector(_vars(p), Z))
     end
 end
+
+function MP.antidifferentiate(m::Monomial{C}, x::PolyVar{C}) where {C}
+    i = findfirst(isequal(x), _vars(m))
+    if (i === nothing || i == 0) || m.z[i] == 0
+        # Insert `x` in the monomial
+        return m * x
+    else
+        z = copy(m.z)
+        z[i] += 1
+        (1 // (m.z[i] + 1)) * Monomial(_vars(m), z)
+    end
+end
+
+function MP.antidifferentiate(p::Polynomial{C,T}, x::PolyVar{C}) where {C,T}
+    # Increase by one the order of `x` in all monomials of `p`
+    q = p * x
+
+    # Find index of `x` in monovec of `q`
+    i = something(findfirst(isequal(x), _vars(q)), 0)
+
+    # Divide the coef of each monomial by `1 + deg(p, x)`
+    # (i.e by `deg(q, x)`)
+    _x = MP.monomials(q)
+    for j in eachindex(_x)
+        q.a[j] //= _x.Z[j][i]
+    end
+
+    return q
+end
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