The present study was performed to check the genetic heterogeneity among five lines of rabbits (A, V, H, LP and R) in terms of functional longevity. The lines A, V, H and LP are maternal lines founded on different criteria and being selected for litter size at weaning. The line R is a paternal line founded and being selected for daily growth rate. The data of each line was analysed using the survival analysis methodology (survival kit program), and the model of analysis was Cox-proportional hazard with frailty term as the additive value of the animals. Another combined analysis was did using the whole data set of all lines. The effective heritability (h2ef) ± sd of functional longevity in each line was 0.11±0.04, 0.06±0.03, 0.17±0.16, 0.002±0.06 and 0.18±0.08 for A, V, H, LP and R lines, respectively. h2ef obtained from the combined analysis of all lines was 0.13±0.02. It can be concluded that the genetic heterogeneity between the studied lines is important.