Abstract The following morphometric variables were examined in 18 primary maxillary first molars at various stages of development, collected from archaeological excavation sites in Israel: perimeters and areas from the occlusal view; buccolingual and mesiodistal dimensions and intercusp distances; the angle between the line joining the distobuccal, mesiobuccal and lingual cusps; and the height of the mesiobuccal cusp. An image-analysing technique comprising a photographic camera, a monitor, a computer with appropriate software and a digital caliper was used. Significant correlations were demonstrated between most variables. Teeth were divided into two groups according to their stage of development: stage one included all teeth at an early stage of development in which mesiobuccal cusp height was less than 5 mm; stage two included all teeth in later stages of development where mesiobuccal cusp height was greater than 5 mm. All external variables showed an increase in size between the two stages (while, among the internal ones, only the angle between the cusps showed a very small increase). The small sample is a limitation but the results suggest the following: (1) growth of the primary maxillary molar crown occurs with ‘bursts’ of development ; and (2) a change in the shape of the crown occurs during its formation where the mesiobuccal cusp moves buccally and distally, and the lingual cusp moves mesially.