This paper presents a critical reflection of the evaluation of learning processes in organizations. Based on learning and evaluation theories and concepts we discuss qualitative and quantitative evaluation processes, and its relationship to short training sessions to foster sustainable development. Short training sessions solve barriers for learning, and support informal learning. Reasons for paying more attention to informal learning are given. Historical cases, like the Dutch cleaner production case, show the role of learning and communication in the process of first and second change towards sustainable development. The NIDO Corporate Social Responsibility case, focusing on system innovation, show that traditional ways of quantitative performance measures, often required by stakeholder, don’t support the lengthy internal qualitative learning process. Cases on different forms of appearance of Microtraining, short training sessions, show improved communication, which might contribute to both first order, and second order change in organizations. These Microtraining sessions appear in formal and informal way, and ask for different evaluation processes. Different ways of evaluating both formal and informal learning are summarized. The traditional ways of evaluation will be valid for planned series of sessions with defined Microtrainer, topic and target group. This matches the traditional way of reporting for internal environmental management systems and certification, like EMAS and ISO. More informal, ad hoc and spontaneously ways of applying short session will need different evaluation methods. We can learn from new approaches in self-assessment and reflection and instruments to asses learning on the job, such as workplace diaries, and guided reflection.