The search for influencing factors and new pathways in aseptic loosening of arthroplasties is a major focus of recent studies. Analyses of polymorphisms of genes revealed a correlation between a specific allele variant and aseptic loosening. The BCL2 gene encoding Bcl-2 with its BCL2 -938C>A polymorphism is a crucial factor of cell cycle control and cell survival. The CALCA -1786T>C polymorphism belongs to the CALCA gene encoding alpha-Calcitonin Gene Related Peptide (CGRP) and Calcitonin. Both proteins are important in bone metabolism and capable to influence the process of aseptic loosening. To date, no studies are reported for aseptic loosening with these two single nucleotide polymorphisms (SNPs). In a retrospective study we determined the distribution of the BCL2-938C>A and the CALCA-1786T>C polymorphisms in 87 subjects with aseptic loosened hip arthroplasties using RFLP and pyrosequencing analysis. Genotype distribution with prognosis of the hip arthroplasty showed neither an association with clinical characteristics of the patients nor the implantation technique. We were unable to detect any influence of these polymorphisms on time to aseptic loosening. motion.