Full text can be accessed at http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2028.2000.00237.x/fullObservations were made of growth rate and variation in colour pattern of the leopard tortoise (Geochelone pardalis babcocki) in northern Tanzania between October 1993 and June 1996. Growth rate differed significantly between tortoises, with immature animals (6.9 ± 1.4 mm month−1) and females (5.7 ± 1.3 mm month−1) exhibiting higher rates of growth than adult animals (2.9 ± 0.8 mm month−1) and males (3.2 ± 1.1 mm month−1), respectively. The faster growth rate in immature animals suggested that growth rate declined with age. The difference in growth rates between the sexes was ascribed to sexual dimorphism, adult females being larger and therefore growing faster than males.