Received wisdom in survey practice suggests that using web mode in the first wave of a panelstudy is not as effective as using interviewers. Based on data from a two-wave mode experiment for the Swiss Household Panel (SHP), this study examines how the use of online data collection in the first wave affects participation in the second wave, and if so, who is affected. The experiment compared the traditional SHP design of telephone interviewing to a mixed-mode design combining a household questionnaire by telephone with individual questionnaires by web and to a web-only design for the household and individual questionnaires. We looked at both participation of the household reference person (HRP) and of all household members in multi-person households. We find no support for a higher dropout at wave 2 of HRPs who followed the mixed-mode protocol or who participated online. Neither do we find much evidence that the association between mode and dropout varies by socio-demographic characteristics. The only exception was that of higher dropout rates among HRPs of larger households in the telephone group, compared to the web-only group. Moreover, the mixed-mode and web-only designs were more successful than the telephone design in enrolling and keeping all eligible household members in multi-person households in the study. In conclusion, the results suggest that using web mode (whether alone or combined with telephone) when starting a new panel shows no clear disadvantage with respect to second wave participation compared with telephone interviews.