Paying attention to development and the earliest possible detection of relevant development disturbances during the first year are among the essential responsibilities of the paediatrician. We present a questionnaire for the documentation of the developmental progress of babies, having been compiled in the Loczy Institute in Budapest, according to the concepts of E. Pikler and J. Falk and based on information furnished by 8871 children. Recorded were 48 items covering motor development, speaking and speech comprehension, hand activities, and the behaviour during feeding and nursing. In coordination with eight paediatricians in private practice, the data of 127 healthy German infants were entered once monthly by the parents. The recorded details correspond as a whole with those of the Denver Development Questionnaire. Differences in the diverse areas between those obtained by the Hungarian and German collectives are discussed. Among the advantages offered by this questionnaire are the simple application and the defined development concept. We recommend this questionnaire for the recording of infantile development for wider use in practices of paediatricians. (Contains 1 table and 5 figures.)