This study reports on the biological properties, antioxidant and antidiabetic, of two varieties of Amaranthus caudatus seeds, Oscar blanco and Victor red. Oil, squalene and phenolic contents were also determined. Seeds of both investigated varieties were found to possess very different levels of squalene (2.2% in Oscar blanco variety and 7.5% in Victor red variety). Although the antioxidant activity of A. caudatus var. Oscar blanco and A. caudatus var. Victor red statistically did not differ significantly from each other (IC₅₀ values of ethyl acetate extracts were 0.50 mg/ml and 0.62 mg/ml, respectively), significant differences were noticed in relation to antidiabetic activity (inhibition of α-amylase, EC 3.2.1.1) of methanolic extracts that showed 50.5% for A. caudatus var. Oscar blanco and 28% for A. caudatus var. Victor red at concentration of 25 μg/ml.