Mortality data from Spain, 1900 to 1992, were analyzed using Gompertzian and Weibull functions. Longitudinal Gompertzian analysis demonstrated that annual age-specific mortality rate distributions were determined by a fixed intersection point (in men: 84.3 years, in women: 89.3 years). Two methods of longitudinal Gompertzian analysis were applied. The method based on linear regression indicated that environmental influences upon age-related mortality were constant. The method based on a rough estimate of first derivative suggested that environmental influences have been decreasing. Both of these methods suggested that genetic influence upon age-related mortality is greater for men that for women. Analysis of Spanish mortality data from 1900 to 1992 suggest that the Gompertz function fits age-specific mortality rate distributions in adult men and women better than the Weibull function.