Recent empirical studies have shown that many employees would prefer to be self-employed and that some employees are engaged in start-up activities. We investigate the factors determining an employee’s preference for being self-employed, entrepreneurial intention and the decision to take steps to start a new venture. We argue that a cluster of psychological characteristics related to the tasks of an entrepreneur in an early stage of the entrepreneurial process, which we call Individual Entrepreneurial Aptitude (IEA), is an important determinant of potential entrepreneurship and early stage start-up activities.