Work is organized based in part on the perceptions, by managers and workers, of workers, their abilities and the characteristics of the work to be done. Physical tasks in factories and services have often been divided into 'light' and 'heavy', a division that often corresponds formally or informally to gender. We have observed the work of cleaners on wards and in offices in an acute-care hospital, using several indicators of workload to identify and characterize typical work situations. 'Heavy' work was characterized by neutral postures, walking, repetitive movements involving the articulations of the upper limb pushing a 1-6 kg (wet or dry) mop, with occasional more intense effort. 'Light' work was characterized by flexed postures, walking, rapid repetitive movements involving the articulations of the upper limb and light weights (dusting) or 1-3 kg weights (emptying wastebaskets), with more occasional intense effort. We did not discover any compelling reason to divide cleaning into 'light' and 'heavy' work. Task assignment by sex may appear to be a solution to excessive job demands which would be better addressed by job re-design.