IntroductionPro-active assessment programs are increasingly used to improve care for older adults. These programs include comprehensive geriatric tailored to individual patient preferences. Evidence for the effects of these programs on patient outcomes is nevertheless scarce or ambiguous. Explaining these dissatisfying results is difficult due to the multi-component nature of the programs. The objective of the current study was to explore and explain the experience of older adults participating in a pro-active assessment program, to help to clarify the effects.MethodsSemi-structured in-depth interviews were held with 25 participants of a pro-active assessment program for frail community-dwelling adults aged 65+. This study was part of an evaluation study on the effects of the program. Transcripts were analysed with thematic analysis and cross-case analysis.ResultsThe participants’ mean age was 78.5 (SD 6.9) and 56% was female. The majority of the participants were satisfied with the program but based this on communication aspects, since only a few of them expressed real program benefits. Participant experiences could be clustered in six themes: (1) All participants expressed the need for a holistic view which was covered in the program, (2) the scope of the CGA was broader than expected or unclear, (3) the program delivered unexpected but valued help, (4) participants described a very low sense of ownership, (5) timing of the program implementation or the CGA was difficult and(6), participants and care workers had a different view on what to consider as a problem. These experiences could be explained by three program components: the degree of (the lack of) integration of the program within usual care, the pro-active screening method and the broader than expected, but appreciated multi-domain approach.ConclusionOlder adults’ need for a holistic view is covered by this outpatient assessment program. However, their engagement and the correct timing of the program are hampered by the pro-active recruitment and the limited integration of the program within existing care. Furthermore, satisfaction seems an insufficient guiding factor when evaluating CGA programs for older adults because it does not reflect the impact of the program.Electronic supplementary materialThe online version of this article (10.1186/s12877-018-1025-7) contains supplementary material, which is available to authorized users.