The aim of this study was to assess the dose- and time-dependent effects of curcumin on bovine spermatozoa during short-term (0h, 2h, 6h) and long-term (12h, 24h) in vitro culture periods. Semen samples were collected from 20 adult breeding bulls, and diluted in physiological saline solution containing 0.5% DMSO together with 0, 1, 5, 10, 50 and 100 μM/L of curcumin. Spermatozoa motion parameters were determined using the SpermVisionTM and CASA (Computer Assisted Semen Analyzer) system. Cell viability was measured using the metabolic activity MTT assay, and the nitroblue-tetrazolium (NBT) test was used to assess the intracellular superoxide formation. The CASA analysis revealed that concentrations of 50 μM/L and 10 μM/L of curcumin were able to significantly prevent the decrease of motility and progressive motility (P<0.001 in case of group B and P<0.01 in case of group C) over all time periods of the in vitro incubation. At the same time, supplementation of concentrations ranging from 50 μM/L to 5 μM/L of curcumin led to a significant preservation of the cell viability in comparison to the control (P<0.001 in case of groups B and C; P<0.05 in case of group D). Concentrations in between 50 μM/L and 5 μM/L of curcumin demonstrated antioxidant properties, translated in a significant reduction of the intracellular superoxide production throughout the in vitro culture (P<0.001). The results indicate that the addition of curcumin, especially in concentrations between 50 μM and 10 μM to the culture medium could be beneficial for a complex enhancement of spermatozoa activity and protection against complications resulting from in vitro culture.