The present study analyses the mediating role of transactional and transformational leadership in the relationship between collective organizational efficacy and collective work engagement. The data was collected from 86 employees working in nine Italian companies of the Food & Beverage sector. The questionnaire included three scales: a) collective organizational efficacy (Bohn, 2010); b) collective work engagement (Schaufeli & Bakker, 2003); c) Multifactor Leadership Questionnaire (MLQ) (Bass & Avolio, 1995). Results showed positive relationship between one component of transactional leadership – contingent reward – and collective work engagement. This result confirms that even if it lacks inspirational appeal in some situations contingent reward could be a rather effective leadership style contributing to employees’ work engagement. Also a positive relationship was found between collective work engagement and three components of transformational leadership – intellectual stimulation, idealized influence (behavior) and idealized influence (attributed) that is consistent with the studies that investigated individual work engagement and leadership. The mediation effects of contingent reward and transformational leadership on the relationship between collective organizational efficacy and collective work engagement were confirmed. This result has an important practical implication: managers can promote collective work engagement through development of a sense of collective organizational efficacy using not only transformational leadership style but also contingent reward. Directions of future research are discussed.