This study reports a comparison of demographics, outdoor recreation activity patterns, and attitudes toward conservation issues collected via mail and online survey methods within a mixed-mode survey. Pennsylvania residents, randomly sampled by Survey Sampling, Inc., were invited in a pre-survey letter to complete the survey online, or through a paper survey mailed to their homes. Differences in outdoor recreation participation were generally small for wildlife-related activities, and were greater among non-wildlife-related outdoor recreation activities, with the Internet respondents generally reporting higher rates of participation. Analyses controlling for demographic variables showed a confounding influence on the relationships examined. Internet respondents tended to be younger, better educated, and more affluent. Conservation- related attitudes did not differ between the mail and online survey respondents and were more weakly related to demographic factors. Results suggest that online surveys can yield valid results when using appropriate sampling designs and implementing quality control procedures.