OBJECTIVES: This study set out to pursue means of reducing mismatch in schoolboy rugby players. The primary objective was to determine whether application of previously reported thresholds of height and grip strength could be used to distinguish those 15-year-old boys appropriate to play under-18 school rugby from their peers. A secondary objective was to obtain normative data for height, weight and grip strength and to assess the variation within that data of current schoolboy rugby players. DESIGN: Cross-sectional cohort study. SETTING: 3 Scottish schools and 'Regional Assessment Centres' organised by the Scottish Rugby Union. PARTICIPANTS: 472 rugby playing youths aged 15 years (Regional Assessment Centres) and 382 schoolboys aged between 12 and 18 years (three schools). OUTCOME MEASURES: Height, weight and grip strength. RESULTS: 97% of 15-year-olds achieved the height and grip strength thresholds based on previous reported values. Larger mean values and wide variation of height, weight and grip strength were recorded in the schoolboy cohort. However, using the mean values of the cohort of 17-year-olds as a new threshold, only 7.7% of 15-year-olds would pass these thresholds. CONCLUSIONS: Large morphological variation was observed in schoolboy rugby players of the same age. Physical maturity tests described in earlier literature as pre-participation screening for contact sports were not applicable to current day 15-year-old rugby players. New criteria were measured and found to be better at identifying those 15-year-old players who had sufficient physical development to play senior school rugby.