Recently, a number of studies have investigated treatments administered via smartphones showing that this treatment format has a potential to be effective. However, we still have limited knowledge of how patients experience this treatment format. The objective of this study was to explore participants' views of a smartphone-based behavioral activation treatment. In-depth interviews were conducted with 12 strategically (participants with different overall experiences) selected participants, suffering from major depression according to the DSM-IV. The interview data were processed with the aid of thematic analysis. The analysis generated the three main themes: Commitment, Treatment and Lack of important components, with attached subthemes. In conclusion, the findings from the current study correspond with existing knowledge in the field of internet-based treatment. Considering that this kind of treatment is still quite new, the need for further research and development is considerable. Nevertheless, its availability, assimilation into users' everyday lives and possible motivational qualities speak of its potential.