Purpose: The etiology of Legg-Calve-Perthes disease (LCPD) remains unknown until today. A few studies have suggested passive smoke inhalation may be a risk factor, although the association is not confirmed and a causal relationship has not been established. Most mothers who smoke during pregnancy may continue smoking after giving a birth, it would be difficult to determine to what extent passive smoke inhalation adds to the risk of LCPD in these children. The causes of Legg-Calve-Perthes disease are largely unknown, but this pediatric disease seems to result from interruption of the blood supply to the proximal femur and is considered a vascular disease. Because maternal smoking during pregnancy influences fetal development and is associated with cardiovascular diseases in offspring, we hypothesized that this exposure and passive Tabaco smoke exposure are risk factors for Legg-Calve-Perthes disease and also investigated other markers of impaired fetal development and early-life exposures. Methods: We prospectively recruited total 96 patients, among those 32 patients with LCPD as a case group and 64 patients attending the hospital for other orthopedic complaints as control group. Conditional logistic regression was used to assess the association between the exposures and risk of LCPD. Results: The main risk factors for LCPD were family background, indoor use of a wood stove, having a family member who smoked indoors (passive smoke) and smoke during pregnancy. Children from the middle socioeconomic group appeared to be at a greater risk of developing LCPD. Conclusions This study provides further evidence that environmental tobacco smoke is associated with an increased risk of LCPD. Family background and exposure to wood smoke also appears to be risk factors. Maternal smoking during pregnancy and other factors indicated by impaired fetal development may be associated with an increased risk of Legg-Calvé-Perthes disease. However, it remains unclear why there are profound differences in the incidence of the disease between regions when the prevalence of smoking is comparable and why bilateral involvement is infrequent, and it needs further study.