Mobile learning is at a leading edge of learning technologies and is at present characterised by pilots and trials that allow mobile technologies to be tested in a variety of learning contexts. The sustained deployment of mobile learning will depend on these pilots and trials, especially their evaluation methodology and reporting. The paper examines a sample of current evaluation practice, based on evidence drawn from conference proceedings, published case studies, and other accounts from the literature and draws on the authors' work in collecting case studies of mobile learning from a range of recent projects. The issues discussed include the apparent objectives of the documented pilots or trials, the nature of the evaluations, instruments and techniques used, and the presentation of findings. The paper reflects on the quality of evaluation in mobile learning pilots and trials, in the broader context of evolving practices in the evaluation of educational technologies