This study was conducted to formulate matrix tablets of diclofenac sodium by melt granulation and to evaluate the effect variation of the concentration of carnauba wax had on the release profile of diclofenac sodium from matrix tablets. Melt granulation of the matrix granules is achieved by mixing a drug powder/or granule with a melt of a wax material (Carnauba wax), with the objective of coating the granules and further retarding drug release from the granules. Four batches of diclofenac sodium granules, DS1, DS2, DS3 and DS4 were prepared by melt granulation using 49.3 %, 43.1 %, 37.0 % and 30.8 % of carnauba wax respectively and then compressed into tablets. The compressed tablets and a control, DSC (VOLTAREN RETARD®) were subjected to quality control tests such as friability, weight uniformity test, crushing strength and dissolution test. Friability(%) value was 1.60, 2.00, 2.30 and 2.60 for DS1, DS2 DS3 and DS4 respectively. The mean tablet weight (mg) was 403.8, 404.3, 403.1 amd 404.2 for DS1, DS2 DS3 and DS4 respectively. The hardness value(Kgf) was 7.0, 7.9,7.8 and 7.0 for DS1, DS2 DS3 and DS4 respectively. From the dissolution test, the % drug release after 2 hours was 1.18±0.00, 1.35±0.00, 1.82±0.01, 4.23±0.00 and 4.79±2.63 for DS1, DS2 DS3, DS4 and DSC respectively. The % drug release after 12 hours was 52.03±0.00, 55.09 ±0.08, 70.78±0.93, 73.00±0.15 and 62.28±2.08 for DS1, DS2 DS3, DS4 and DSC respectively. The higher the concentration of carnauba wax, the slower the drug release from the matrix tablet.