The aim of this study was to investigate the effects of methionine and lipoic acid on ram sperm parameters during liquid storage (5 °C). Ejaculates collected from five Merino rams were pooled at 37 °C. Each pooled ejaculate was divided into five equal aliquots and diluted (37 °C) with five extenders, one of which was without additives, two of which contained methionine at two different doses, and the other two of which contained lipoic acid at two different doses. Sperm parameters were determined at 0, 24, 48, 72 and 96. h of liquid storage at 5 °C. The extenders containing 2 and 4. mM of methionine resulted in higher motility percentages, in comparison to the control, up to 96. h of storage. Methionine at doses of 2 and 4. mM led to higher viability and sperm mitochondrial activity percentages, when compared to the controls during 48, 72 and 96. h of liquid storage (P< 0.05). The findings of this study showed that methionine was of greater benefit to ram sperm parameters during liquid storage. © 2012.