Abstract: Procurement practices are a set of activities undertaken by an organization to promote effective management of its supply chain (Sollish & Semanik, 2012).The main purpose of the study was to establish the effect of procurement practices on performance of commercial state owned enterprises in Nairobi County. The specific objectives of the study were to establish the effect of buyer-supplier relationships on performance of commercial state owned enterprises in Nairobi County, to establish the effect of supplier selection procedures on performance of commercial state owned enterprises in Nairobi County, to determine how organizational capacity affect performance of commercial state owned enterprises in Nairobi County and to ascertain the effect of procurement process management on performance of commercial state owned enterprises in Nairobi County. The study adopted a descriptive survey design. Primary data was collected using questionnaires targeting managers in Finance, Procurement, Production and Sales and Marketing departments in each enterprise. The study achieved 80% response rate since ninety six (96) out of the 120 questionnaires administered were filled and returned. The population of the study comprised of thirty eight (38) commercial state owned enterprises operating in Nairobi county. A random sample of thirty (30) enterprises representing 78.95% was selected.