In a rapidly changing economy, training firms are intended to play a special role. Their services facilitate updating information, raising the staff competence, executing improvement projects etc. However the training firms should continuously improve their activities as well. This article identifies a set of seven development mechanisms used by training firms. Afterwards, basing on the information supplied by 90 managers of training firms, it validates the effectiveness and popularity of each mechanism. According to the respondents of the research the most successful mechanisms are: (1) improving training methods i.e. developing the competences of coaches, introducing new training methods and techniques, etc., (2) preparing and improving standards for the training materials which are... handed out to the training participants and (3) noticing nonconformities i.e. collecting and analyzing information concerning problems appearing in the carried out activities (basing among others on client’s opinion, complaints, internal audits) and using them to introduce corrective actions.