Objective: Children are universally considered to be the most important asset for any nation. The main aims of the present study were 1) to investigate the causation of discomfort related to working postures 2) to assess the physiological strain among the child farmers and 3) to assess the thermal stress during work in an agricultural field. Methods: For this study, 120 child agricultural workers and 120 control subjects aged 10-16 years were selected randomly, and a detailed posture analysis was performed among them by REBA and OWAS methods. The Modified Nordic Questionnaire was applied to assess the discomfort felt among both groups of workers. Physiological assessment of workload was carried out by recording the heart rate and blood pressure of the workers prior to work and just after work in the field. Results: Child agricultural workers suffered from pain especially in the low back (98%), knees (88%), hands (82%), shoulder (77%) and neck (68%). Among the agricultural activities in potato cultivation, the child potato workers, felt discomfort during spading (99%), sprinkling water (90%) and picking crops (87%). The post-activity heart rate of the child agricultural workers was 170.1 beats/min, whereas the systolic and diastolic blood pressures were 129.0 and 67.0 mm/Hg respectively. Conclusions: Most of the agricultural activities in potato cultivation were strenuous ones that affect the children, who suffered from acute pain and discomfort for a long period of time, which mainly hampers and restricts their education.(J Occup Health 2013; 55: 244-258)