This study attempted to measure the prevalence of lower limb clinical rickets using a rapid assessment methodology in Cox’s Bazaar, a coastal district of Bangladesh. The study populations were drawn from 28 random villages representing all seven ‘thanas’ (subdistricts) of the district. Data were collected on 25 891 children and young people aged 1–20 years in two phases. In the first phase, 30 trained, local, non-medical people listed 490 children suffering from visible signs of any physical disability. To achieve this, they demonstrated a multicoloured poster showing the features of lower limb clinical rickets to key informants in the villages. In the second phase, two teams of medically trained people (physicians), each with one male and one female, validated the above cases for rickets. They verified and validated 278 cases in five thanas. Due to inclement weather and floods, they could not visit the other two thanas. Based on these data, the adjusted prevalence rates for lower limb clinical rickets were calculated to be 931 per 100 000 population (95% confidence intervals 795–1067). The prevalence was highest (1215) in children aged 1–4 years and lowest (498) amongst 17–20 year olds. Females had lower prevalence than males. Based on the study experience, a quick investigation using a similar methodology was performed in five other districts (Sunamganj, Noakhali, Bhola, Jessore and Gaibandha), and clinical signs of lower limb rickets were found in Sunamganj and Jessore. It thus indicates that rickets may be endemic, not only in Cox’s Bazaar but also in some other parts of Bangladesh. The methodology used for this study was found to be rapid, simple, replicable and inexpensive.