People with congenital profound deafness (CPD) were surveyed in the general population of Sichuan. The prevalence was 0.082% (104/126, 876) of the general population, male 0.086%, female 0.078%. There was no significant difference in prevalence between urban and rural populations. However the population living in the mountains had a much higher prevalence than people from the foothills and plains (P < 0.05). Amongst the nationalities investigated, there were significant differences in prevalence. Non-Chinese, except for Tibetans, presented a significantly higher prevalence than Han Chinese. There was a significantly higher prevalence among the inbred population (0.82%) than among the non-inbred population (0.72%). An effect of parental age was demonstrated, but no effect of birth order was found. There was a significant seasonal variation in prevalence. Inherited cases could account for 71.2% of all cases, of which 92% were autosomal recessive (AR) and 8% autosomal dominant (AD). Heterogeneity in AR was found with at least 8 different loci. The fitness was 60.26%, the coefficient of selection was 0.3974, mutation rate was estimated to be 2.0 x 10(-4), and no heterozygote advantage was proven.