Research has been on-going on many plant materials, especially those discarded as waste, to exploit their nutritional and antinutritional properties. This is as a result of the United Nations’ millennium development goal to eradicate extreme poverty and hunger. Avocado (Persea americana Mill) seeds are often discarded after taking the pulp of the fruit. This study is aimed at evaluating the effect of processing methods (soaking and boiling for various periods) on the nutritive values and antinutritional factors of Persea americana seed as a step towards establishing purposeful utilization of the seed. The processed avocado seeds were evaluated for proximate, mineral, antinutritional factors, and vitamin compositions. Raw avocado seed had the lowest moisture content (73.69%) while the soaked seeds had the highest moisture content (80.73%). Analysis of variance (ANOVA) showed significant differences (p < 0.05) in moisture, crude protein, crude fat, ash contents, crude fibre, carbohydrate, vitamins C and E and mineral contents at different processing methods. Boiling of the seeds for 15, 20 and 25 minutes reduced the vitamin A content of the seed by 16%, 13% and 15% as compared with the raw seeds. Soaking of seeds only reduced vitamin A content by 3%. There was high percentage reduction of vitamin C content (81%) in seeds soaked in water as compared with raw seeds. Percentage reduction of vitamin E contents ranged between 4.0% - 7.0%. The raw seeds had the highest content of sodium, calcium and potassium. Soaking reduced the tannin, phytic acid, alkaloid, saponin and oxalate contents of the seeds by 65%, 58%, 64%, 48% and 49% respectively. Boiling for 25 minutes also reduced the tannin, phytic acid, alkaloid, saponin and oxalate contents by 75%, 53%, 79%, 21% and 32% respectively. In general, soaking and boiling of the avocado seeds reduced the antinutritional factors to a large extent.