Lithuanian patients with visual problems were clinically examined for retinitis pigmentosa (RP). Out of more than 70 clinically and genealogically tested patients with familial retinal degenerations, 33 unrelated families with autosomal dominant RP (adRP) were identified. Screening for mutations in the rhodopsin (RHO) and polymorphisms in the peripherin/RDS (RDS) genes was initially performed in the adRP patients using DNA heteroduplex (HD) analysis. Direct DNA sequencing in the cases of heteroduplex formation showed the presence of the following mutations and polymorphisms in 14 adRP patients: RHO gene mutations - Lys248Arg (one case), and Pro347Leu (two cases) and RDS gene polymorphisms - Glu304Gln (12 cases), Lys310Arg (5 cases), and Gly338Asp (12 cases). The presence of these changes in nucleotide sequence (except Lys248Arg in the RHO gene) was confirmed by relevant restriction enzyme digestion. Since RHO gene mutation Pro347Leu has been shown to be related to adRP, early diagnosis of adRP is possible in the corresponding families. On the other hand, RDS gene mutations Glu304Gln, Lys310Arg, and Gly338Asp appear to be polypeptide polymorphisms not related to adRP. Low prevalence of adRP causing mutations identified in the RHO gene and similar distribution of the peripherin/RDS amino acid polymorphisms in the Lithuanian adRP probands imply the presence of genetic peculiarities of the Lithuanian population in comparison to other European populations.