Purpose – To examine organizational diagnostics taken from the best practice model of change as organizational diagnostic factors in a specific type of business such as family businesses. These account for many of companies in Asia and are regarded as a special from the mixture of management focus on business, family and ownership. Design/methodology/approach – In order to manage changes in family business successfully, the organizational diagnostic factors are analyzed from executives' in-depth interviews with Thai family businesses that implement new IT systems. Findings – Communication, generation, ownership, family structure, politics and national culture are six diagnostic factors in Thai family businesses that are not the same as the model of change. Originality/value – Consultants and change agents in family businesses, especially in Asia, can use these factors as an additional guideline for their effective change management.