The GNU Multiple Precision Arithmetic Library (GMP) provides access to heavily optimised structures that allow to efficiently perform exact integer and rational computations. Julia has native support for the arbitrarily-sized integer structure from GMP, through the BigInt type, but does not provide a full interface for GMP's rational numbers (although it is internally used for Julia's native Rational{BigInt} type). As part of this work, we provided this special support in a separate package, BigRationals.jl, which exports the BigRational type wrapping GMP's rational type.