A comparison of external parasitic infestations among inhabitants of Legnica, Wałbrzych, and Wrocław districts, in the Lower Silesia region of Poland showed a direct relationship between the high incidence of scabies and low standard ecological indices, as well as social economic setting of the communities. In the years 1990–1997, the highest mean incidences of scabies per 100,000 people (80 and 46) were noted, respectively, in the Legnica and Wałbrzych districts, compared to only 7.9 in the Wrocław district. Infestation was correlated with percentages of the population with higher education (4.8; 4.2, 10.1, respectively) and the number of patients per physician (795, 632, 288, respectively), and the percentages of degraded land/and land threatened by degradation (10/37, 5/16, 0.7/10, respectively), forest stands damaged by gases and particulates (99.4, 99.4, 58.8, respectively), and air pollution emission indices in the towns of Legnica and Wałbrzych (30 and 21 tons/km²) and Wrocław (16). Scabies infestation was highest in children and teenagers (0–19) and was gender-associated (in all age groups, women were more often infested than men). A decreasing rate of scabies infestation, especially from the mid-1990s, was noted for both scabies and pediculosis in Wałbrzych district; in the 0–19-yr-old inhabitants, it varied from 0.75% in 1994 to 0.41% in 1996.