The occlusal surfaces of deciduous upper second molars in the Japanese population were measured with the aid of moiré contourography. The mean values of the cusp heights and intercuspal distances were larger in females than in males, although these differences were insignificant except for the distance between the paracone and metacone. When the results obtained were compared with those permanent first molars, the crown size was smaller in deciduous than in permanent molars, especially. the height of the hypocone and the intercuspal distances in the buccolingual direction. Low correlations between the cusp heights and the intercusal distances in the permanent molara were also found in deciduous molars, suggesting that the cusp height of the human deciduous molar is independent from the transverse size of the crown.