This study examined the computer aided modelling, analysis, and design, of a concrete gravity dam. Manual design was first done and validated with CADAM software. MIDAS GTS software was then used again and the results were compared with manual design based on stability analysis against sliding, overturning and shear friction. Initial data of the University of Ilorin dam was collected from project planning unit (PPU) of the University of Ilorin for the analysis. A Typical trapezoidal concrete gravity dam ofTop width of 2m, Bottom width of 10m, Height of12m and upstream face batter of 0.9m was analysed in this study using the Gravity Method of analysis.Based on the manual design of the typical concrete gravity dam analysis carried out, the factors of safety against overturning, sliding and shear friction factor were 1.63, 1.15, and 20.59, while validation using CADAM gave 3.63, 4.08 and 5.66 factor of safety respectively. These are all greater than the allowable factors. The compressive stresses at the toe of the dam using manual design and MIDAS software are 1.05X kN/ and 1.66X kN/ respectively and the shear stresses using manual design and MIDAS software are 6.21X kN/ and 6.41X kN/ respectively. The results from the manual analysis and Midas GTS Software differ slightly; this could be due to the methods used.