We previously showed by cytogenetics and fluorescence in situ hybridization (FISH) that the most common chromosomal abnormality in renal oncocytomas is loss of chromosome 1 or 1p. In the present study, we evaluated chromosome 1 by loss of heterozygosity (LOH) studies. DNA was extracted from paraffin sections. Three microsatellite markers were used: D1S508, D1S199, and D1S2734. The regions targeted by FISH probes and LOH markers were close to each other but not overlapping. Among 16 tumors evaluated by all 3 techniques, in 2 cases, LOH could not be interpreted. LOH was detected in at least 1 locus in 12 (86%) of 14 renal oncocytomas studied, with other loci being noninformative or not interpretable (1 case). In 2 cases, the LOH results were inconclusive. These results provide further evidence to support widespread abnormalities in chromosome 1p in renal oncocytoma. Determining whether such abnormalities are unique to renal oncocytomas or are also present in other tumors requires further studies.