What are the characteristics of the Colombian business groups and how did they evolve between 1950 and 1985? How did the characteristics change during a period of deglobalisation? This paper provides a description of the Colombian business groups. It tracks the evolution of 25 groups since their consolidation in the 1950s, during a period of Industrialization by Substitution of Imports (ISI), until 1985, a year before the Colombian government considered for the first time trade liberalisation policies. By concentrating on descriptive variables such as size, ownership and control, foundation year, and diversification, this paper provides an overview of the consolidation, development and restructuring of the groups. The task implied answering the underlying questions of what and who the business groups are by relying extensively on secondary literature for the main concepts and primary sources, valued for their ‘first-handedness’, to illustrate and complement the arguments on their characteristics. Combining the analysis of the track record of 25 groups, this research places the business group as the unit of analysis, and also includes 428 group-affiliated firms. Despite their current importance and presence in the economy since the second half of the twentieth century, a profile of the largest Colombian business groups during this period has not yet been produced. Most of the variables used to characterise the groups are the ones set out by the literature, however, the paper also brings indexes to quantify the historical evolution of the characteristics.