This paper proposes an exponential estimator of a population mean under double sampling using one auxiliary variable. The proposed estimator is modified from the estimator of Khatua and Misha (2013) and Ozgul and Cingi (2014). The bias and mean square error of the proposed estimator are derived under the second order of approximation. The efficiency of the proposed estimator is compared with the existing estimators based on mean square error. The results indicate that the proposed estimator is more efficient than others under empirical study with real datasets.