Background Patient portals are increasingly being implemented worldwide to ensure that patients have timely access to their health data, including patients’ access to their electronic health records. In Sweden, the e-service Journalen is a national patient-accessible electronic health record (PAEHR), accessible on the web through the national patient portal. User characteristics and perceived benefits of using a PAEHR will influence behavioral intentions to use and adoption; however, poor usability, which increases effort expectancy, may have a negative impact. Therefore, it is of interest to further explore how users of the PAEHR Journalen perceive its usability and usefulness. Objective On the basis of the analysis of the survey respondents’ experiences of the usability of the Swedish PAEHR, this study aimed to identify specific usability problems that may need to be addressed in the future. Methods A survey study was conducted to elicit opinions and experiences of patients using Journalen. Data were collected from June to October 2016. The questionnaire included a free-text question regarding the usability of the system, and the responses were analyzed using content analysis with a sociotechnical framework as guidance when grouping identified usability issues. Results During the survey period, 423,141 users logged into Journalen, of whom 2587 (0.61%) completed the survey (unique users who logged in; response rate 0.61%). Of the 2587 respondents, 186 (7.19%) provided free-text comments on the usability questions. The analysis resulted in 19 categories, which could be grouped under 7 of the 8 dimensions in the sociotechnical framework of Sittig and Singh. The most frequently mentioned problems were related to regional access limitations, structure and navigation of the patient portal, and language and understanding. Conclusions Although the survey respondents, who were also end users of the PAEHR Journalen, were overall satisfied with its usability, they also experienced important challenges when accessing their records. For all patients to be able to reap the benefits of record access, it is essential to understand both the usability challenges they encounter and, more broadly, how policies, regulations, and technical implementation decisions affect the usefulness of record access. The results presented here are specific to the Swedish PAEHR Journalen but also provide important insights into how design and implementation of record access can be improved in any context.