Robertsonian translocations, occurring with a frequency of about 1 in 10,000 livebirths, may be an important cause of uniparental disomy as demonstrated for 13/15, 13/14, 14/14, and 22/22 translocations. Dysmorphogenesis and/or mental retardation provide clinical clues for uniparental disomy in apparently balanced offspring of translocation carriers. Research strategies for assessing frequency and implications of uniparental disomy in translocation carriers include a genetic register approach, study of abortuses from balanced translocation carriers, and parent-of-origin studies on de novo homologous Robertsonian translocations.