Casuarina equisetifolia is an actinorhizal tree being introduced in agroforestry systems of Pakistan. A study was conducted to observe the seasonal changes in nodular nitrogenase activity (C2H2 reduction) and uptake hydrogenase activity of C. equisetifolia. Nodules showed significant (P≤0.05) seasonal variation in the nitrogenase and hydrogenase activities which were highest during June (13.52 μmoles C2H4‧g^(-1) fresh nodule wt. hr^(-1) and 2.55 μmoles H2 consumed g^(-1) fresh nodule wt. hr^(-1), respectively) and lowest during December (0.55 μmoles C2H4‧g^(-1) fresh nodule wt. hr^(-1) and 0.23 μmoles H2 consumed g^(-1) fresh nodule wt. hr^(-1), respectively). This study has many important and applied ecological implications in the management of horticulture and agroforestry systems of the tropics.