In a group of 254 Irish males aged 17 to 20 years the anthropometric variables height, weight, bulk index, percentage of fat, fat free weight were measured and the following aspects of posture assessed: kyphosis, lordosis, scoliosis, abducted scapulae, ankle posture, foot eversion, foot flatness. Social group was determined according to father's occupation and certain other social information was collected. There were social group differences in height, weight, percentage fat and fat free weight. Subjects of social group V were small and light and had a lower fat free weight than the other groups, while those of Group I tended to be tall and heavy. Farmers' sons tended to be relatively tall but with little body fat. There were also urban-rural differences in physique. There were significant social-group differences in lordosis, scoliosis, abducted scapulae, foot posture and overall posture, and urban-rural differences in lordosis, abducted scapulae, foot flatness and overall posture. There was no evidence that posture was influenced by the measures of phsique used in this study, and the individual components of posture were independent of one another. Posture was not influenced by whether or not the subject's school employed a qualified physical education teacher.