The effects of computer encoding on fatigue were analyzed by conducting a controlled experiment. Three independent variables were considered, namely; two screen viewing angles, two types of chair used and the presence/absence of wrist support. A full factorial design was used and counterbalanced using Latin Square 8x8 design. The experiment was conducted in a real work em7ronmenr where the encoders do their usual tasks. The type of chair used turned out to be a significant factor on fatigue symptoms such as feeling of tiredness, desire to lie down, low back pain and shoulder stiffness. There were no significant factors identified in the responses: critical fusion frequency (CFF), eyestrain, “apt to commit mistakes" and productivity. Viewing angle and the presence of wrist support were not significant factors in any of the responses considered in the experiment. There were no statistically significant interactions identified in the experiment.