The development of vibration syndrome among chipping and grinding workers at foundries and a shipyard was investigated. Workers completed questionnaires concerning use of vibrating hand tools outside the job and underwent a medical examination including sensory tests of the hands and fingers. Workers who used pneumatic chipping hammers on the job but did not use other vibrating hand tools were examined. Vibration syndrome development was classified by stages from asymptomatic through stages characterized by tingling or numbness, to stages 1 to 3 involving initial to advanced blanching. Seventeen percent of exposed workers at the foundries were asymptomatic compared to 36 percent of shipyard workers. Twenty, 22, and 5 percent of foundry workers were in the three respective stages of blanching, compared to 9, 5, and 5 percent of shipyard workers. The percent of workers in stages 1 to 3 of blanching was directly and significantly related to the number of years on jobs using chipping hammers or grinding tools. When hourly workers were compared to incentive or piece workers, 19 percent of hourly shipyard chippers and grinders and 28 percent of hourly foundry chippers and grinders had vibration syndrome in stages 1 to 3. Among incentive chippers and grinders at foundries this value was increased to 42.5 percent, and for incentive chippers and grinders doing intricate work, 49 percent showed vibration syndrome in stages 1 to 3. The authors conclude that incentive workers, working more quickly and steadily to increase their earnings do more chipping and grinding, producing increased severity of vibration syndrome. Shipyard workers tend to have more training in tool grip and have more time off waiting for other jobs to be completed. Development of vibration syndrome is related to the duration and intensity of chipping and grinding work performed.