Background: When diagnosing cancer, it is often difficult to predict the further growth and spread of the tumour. One of the features of cancer is an abnormality in the amount of DNA in cancer cell nuclei, so-called DNA aneuploidy. Extensive abnormalities are often due to an unstable genome, which leads to an accumulation of mutations, dysregulation of genes and loss of cell cycle control. This article aims to provide an overview of the prognostic value of DNA ploidy analyses in ovarian, endometrial, prostate and colorectal carcinoma., Material and Method: This review article is based on literature searches in PubMed for the period 2000–2016., Results: The search resulted in 308 articles. Thirty-three of these, representing an analysis of more than 18 000 tumours, fulfilled the inclusion criteria. In 30 of the 33 articles, a significant correlation was found between DNA ploidy and disease outcome for patients with ovarian, endometrial, prostate and colorectal carcinoma. Patients with aneuploid tumours had a poorer prognosis than those with diploid tumours., Interpretation: DNA ploidy analysis is a prognostic method for patients with ovarian and endometrial carcinoma, and is used as a guide to options for supplemental treatment and fertility-sparing surgery. A review of publications in recent years of DNA ploidy analyses for prostate and colorectal carcinoma reveals that these patient groups may also benefit from these measurements. In general terms, DNA ploidy analyses may help to increase knowledge of who needs supplemental treatment and who does not – which may be advantageous in avoiding overtreatment.