Background: Developmental testing in children is concerned mainly with a pass or fail on tasks such as grasping, manipulating and inserting. Knowledge about the qualitative development of hand movements in young children is scarce. Aim: We studied the qualitative development of manipulative hand movements in 14-, 18- and 25-month-olds. Study design and subjects: Twenty-six children were videoed during grasping, manipulating and inserting cubes into a cup or box and pegs into a peg-board. Results: We found clear-cut, object-related results. The right hand was used mainly to grasp, manipulate and insert the pegs, while no hand preference was found for the cube. Generally, the quality of grasping and inserting did not change with age. At 18 months, the performance was more optimal if the children used pegs rather than cubes. The adjustment of hand opening became more adapted with increasing age when grasping the cubes; this was not observed for the pegs. Associated movements occurred less during pegging than while playing with the cubes. A variety of patterns were used for pegging. Besides a difference in band preference between girls and boys, some patterns became more prominent with increasing age. The success rate increased with age but was independent of the pattern used. Conclusion: This study stresses the need of a clear understanding of the entire spectrum of normal motor development. This knowledge forms the basis on which abnormalities, even of such common movement patterns as grasping, manipulating and inserting, can be reliably diagnosed in neurologically impaired infants and children. (C) 2003 Elsevier Ireland Ltd. All rights reserved.