Existing software engineering and organization development literature acknowledges that there are fundamental operational differences between small and large organizations. Despite this recognition, there has been no attempt to verify whether small and large software organizations implement software process improvement (SPI) programs differently in order to advance their businesses.This study examines whether an organization's size affects its SPI implementation strategy and the degree of SPI success. Based on an extensive literature review of critical factors of quality management, organizational learning, and SPI, a survey questionnaire was developed and data on the implementation of six organizational factors and the resulting organizational performance was collected through a mail survey of 120 software organizations. The findings show that small organizations reported that they implement SPI elements as effectively as large organizations, and in turn, achieve high organizational performance. The main lesson to be learned from this study is that to implement SPI at least as effectively as their large counterparts, small software organizations should capitalize on their relative strengths in employee participation and exploration of new knowledge.