Thorough knowledge of the physical properties of cashew nuts in its present form is necessary in the design of its shelling machine. A study was carried out to determine the effects of pre-treatment by hot oil roasting and steam boiling on the physical properties of cashew nut. Samples of cashew nuts obtained from five plantations in Iseyin area of Oyo State and Iwo in Osun State in the South-Western Nigeria were used in this work. About 3kg of nuts were picked from 20 randomly selected trees in each of the plantations. The cashew nuts were subjected to pre-treatment by steam boiling and hot oil roasting. The physical properties of raw and pre-treated cashew nuts were determined using standard methods. The results showed that nuts from South-Western Nigeria, which were used for the experiment, could be classified as medium large and extra large ie 22-35 mm. The pre-shelling treatment showed significant difference (P<0.05) in the means of length and width of cashew nut, and no significant difference for thickness, aspect ratio and sphericity index. The treatment showed significant difference (P<0.05) in true and bulk densities but showed no difference in the porosities of the nuts. The moisture content of raw kernel was significantly different (P<0.05) from that of roasted and steam-boiled kernels. The physical properties of cashew nuts were found to be affected by pre-treatment by hot oil roasting and steam boiling.