Purpose ' This paper aims to contribute to the debate on employee performance by discussing the importance of trust in encouraging performance. Design/methodology/approach ' Based on a literature review of discretionary contributions to the organization and employee trust in their leaders. Findings ' There is strong evidence that the vulnerability of employees in the employment relationship has increased the importance of trust in encouraging employee extra-role behaviour outside their legal and contractual obligation. Research limitations/implications ' The importance of trust for employee behaviour has been well documented but the fragility of the psychological contract shows that discretionary extra-role behaviour will be context specific. Practical implications ' Organizations need employees to perform beyond expectations and this paper shows the importance of trust in encouraging this performance. Originality/value ' This paper is important for managers and academics because of the imperative of being able to access and then use the knowledge and skills of employees.