The objective of this research project was to determine the key variables that impede organisational learning in a high growth start-up business unit environment. The value of high growth business units or firms lies in their immediate contribution to wealth creation and employment, although the success rate of firms and business units are low due to the inherent managerial complexities in the high growth environment. This research project contributes to the body of knowledge on high growth start-up firms by identifying, testing and rating variables that impede organisational learning, as well as providing a new construct. A survey was done to identify variables that may impede organisational learning and a sub-set of variables were identified in the categories of orientation factors, human resources practises, systems and structures, knowledge management practises and communication. Twenty propositions were formulated. A qualitative research methodology, using case research and in-depth interviews, was used to rate the relative impeding effect of the twenty variables on organisational learning in an actual high start-up business unit environment. The results indicated that 6 key variables had the highest impact on organisational learning. These variables were: a lack of common and shared logic, selection of inappropriate managers, a lack of teamwork, inappropriate systems (processes and software), a lack of networks and a lack of communication. Although the results may not be generalised due to a lack of a statistical base, management may already be alerted to consider these variables when starting up a new high growth venture.