Software-developing Small and Medium Enterprises (SMEs) usually make investments with little resources and under severe pressures imposed by competiveness and productivity needs. From the analysis of the characteristics of software-developing SMEs and changes affecting Software Engineering Tools (SETs). we have suggested criteria to support the evaluation and selection of tools that best suit their needs. These criteria have been developed based on ISO/IEC 14102, adopting their guidance on the assessment and selection process. For purposes of their validation, we have applied such criteria to three SETs. We expect that these criteria will provide support to establishing a tool selection model. © 2008 IEEE.