Fermented castor bean, melon, and African locust bean seeds serve as a protein source in the diet of many Nigerians. Proximate and mineral composition changes during fermentation remain underexplored, particularly in comparative contexts. This study aimed to evaluate and compare these seeds' proximate and mineral compositions during controlled fermentation. Raw seeds were sourced from local markets and subjected to traditional fermentation processes for seven days in the laboratory. Proximate analysis was conducted using standard methods, while mineral contents were quantified using flame photometry after ashing. Analysis of Variance was used to determine a significant difference. Comparatively, at the end of the fermentation, the highest protein (39.96 ± 0.76%), fibre (8.03 ± 0.26%), ash (4.20 ± 0.00%), carbohydrate (13.10 ± 1.25%) and moisture (16.55 ± 0.79%) were recorded in fermented African locust bean seeds. The highest fat content was recorded in castor bean seeds (45.80 ± 0.62%). Comparative mineral composition at the end of fermentation showed that the highest zinc (3.31 ± 0.29 mg/ 100 g), magnesium (282.56 ± 2.03 mg/ 100 g), and calcium (220.00 ± 1.20 mg/ 100 g) were recorded in fermented African locust bean seeds. The highest potassium (1307.85 ± 5.87%) and sodium (55.93 ± 0.96 mg/ 100 g) contents were recorded in melon and castor bean seeds, respectively. This study suggests that fermentation enhances traditional condiments' nutritional and mineral value in West African cuisine. These findings support process optimisation, especially for African locust bean seed to inform dietary recommendations.