In this paper, two new maximum likelihood methods are proposed to estimate the unknown sample size n in a simple random sample from an absolutely continuous population. These methods are based on the number of records and the record values in the sample. The use of these methods is explored through simulations. An application to a real data set is also included. (C) 2015 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.V. All rights reserved.