A case of a stillborn Norwegian Forest kitten characterised in the course of anatomopathological and genetic examination is reported. The hydatidiform mole was diagnosed by delayed development, low birth weight of the kitten and abnormal placental development. Anatomopathological diagnosis was confirmed in genetic tests based on the amplification of highly heterozygous microsatellite sequences located on the X (FCA311) and autosomal chromosomes (FCA506, FCA532 and FCA178), as well as the sex-specific Sry and amelogenin (Amel) genes. The presence of two microsatellite alleles of paternal origin and one allele of maternal origin was observed in all analysed tissues (kidney, liver, brain, heart and spleen) of the stillborn kitten. The kitten's sex was diagnosed by the presence of the paternal Sry gene, and maternal and paternal products of Amel, as well as one maternal and one paternal X chromosome FCA311 microsatellite allele. The results thus confirmed that the haploid egg was fertilised by two sperm, yielding a triploid karyotype. In summary, the successful application of genetic markers in postnatal diagnosis of this condition in the cat confirms considerable usefulness of these techniques, especially in cases where cytogenetic diagnosis is insufficient or impossible.