The aim of the study was to analyse factors influencing the occurrence of accidents in materials handling. The supervisors’ and workers’ opinions about deficiencies and problems in the accident prevention during materials handling were surveyed. Materials handling in this study will mean all internal transfers at the construction site, work site storage, installation and removal of formwork, and installation of pre-cast concrete units. Altogether 422 accident report forms were analysed. Sixty-four per cent of the accidentsthat occurred at office and public building construction sites took place during construction of theframework. The corresponding percentage for accidents occurring during construction of the framework of high-rise apartment houses was 44%, that for terrace houses was 40%, for industrial sites 55%, and for building repair and renovation 50%. In the questionnaire study the data obtained from the site supervisors can be used to search for the basic reasons behind the problems. The opinions of the workers dealt more with how the basic problems were expressed at the practical level. The serious accidents (45 cases) investigated by the National Board of Labour Protection were classified according to the type of accidents.