Computer has been incorporated into day to day activities of almost every field of human endeavour, offices to different shops. Therefore many people are now working with computer for longer hours of time. There is no doubt that this incorporation of computer has helped users a lot but it also brings problems to the users. One of the problems is Repetitive Strain Injury (RSI). Five hundred and thirty one (531) questionnaires were personally administered to different categories of people that use computer in various works of life, ranging from banking sector, civil service, educational sector, health sector to private sector. The distribution cut across different professions. A statistical analysis was conducted on the data obtained using frequency distribution, Pearson Correlation and Linear Regression. The result obtained showed that 94.3% of the respondents suffered pain from one or more parts of the body. 86.8% of the respondents suffered from eyestrain, 63.9% suffered from low back pain, 67.4% with wrist pain, 64.7% finger pain while the least suffered pain was foot pain which only 19% responded positively to it. There are significant relationships between duration of computer usage, type of chair used, type and size of monitor used and the incidence of RSI. RSI modeled was formulated through linear regression which showed that a unit change in computer will result in corresponding 1.76 unit increases in RSI and a unit change in ergonomic deficiency will also result in corresponding 0.66 increases in RSI. The existence of RSI was established and it was discovered that the more time spent on the computer system, the more the proximity of having strain or pain in one or more part(s) of the body.