This study is an attempt to test a framework that looks into how relationships in internal and external logistics factors contribute to the success of firms in the electrical and electronics industry in Thailand. Data were collected from the 303 firms in the electrical and electronics industry in Thailand. The analysis was divided into two scenarios based on the firm's capital investment (less than or higher than 200 million Baht). Questionnaires were used as a tool to collect data and structural equation modelling (SEM) was used to analyse relationships among these factors. Seven hypothesised relationships were tested on five factors which consisted of human resource management, logistics infrastructure, internal operational activities, external operational activities and business performance. The results show some support for some of the hypotheses and make a contribution to the understanding of the influence of internal and external logistics factors on business performance based on the size of the firms. The outcomes can recommend important logistics factors to the firms in each scenario so they can focus more on these factors with their limited resources and budgets. Copyright © 2013 Inderscience Enterprises Ltd.