This document presents an improved Apriori algorithm for generating frequent item sets on large datasets using Hadoop MapReduce. The classical Apriori algorithm suffers from repeated database scans, high candidate generation costs, and memory issues. The proposed improved Apriori algorithm aims to address these issues by leveraging Hadoop MapReduce to parallelize the processing and reduce unnecessary database scans. It presents the pseudocode for the classical and improved algorithms. The improved algorithm is evaluated to show it provides better performance than the classical Apriori algorithm in terms of time and number of iterations required.