Background. Due to the ongoing COVID-19-pandemic and the need to improve health protection, companies in many countries have been encouraged to offer their employees more work-from-home (WFH) opportunities when possible, which is often the case with office work. WFH offers advantages and disadvantages in terms of work design and, as a consequence, employee health. Due to their health effects, rest breaks are a work factor that is strongly regulated by national legislation. However, their organization at different locations of work has been so far largely unclear. The aim of this study was to clarify if WFH affects employees' compliance with mandatory break regulations and if rest break behavior relates to physical and mental health complaints.Methods. This cross-sectional study relies on survey data (10-12/2020, prior to/during the 2nd pandemic wave in Germany) from 534 office workers working in the office (n = 391) or at least partially from home (n = 143). We assessed their compliance with six mandatory rest break criteria according to German legislation (i.e., total rest break duration, single break duration, no interruptions, no skipping, scheduled/predictable, regular leaving of visual display workplaces and/or regular short rest break) and physical (muscular tension, headache) as well as mental (exhaustion, depressive mood) health complaints.Results. Ninety-two percent reported at least one violation of these rest break principles. WFH (frequency) did not affect the (non-)compliance with these regulations but was associated with increased risk for muscular tension (OR = 1.93). Frequent break skipping increased risk of headache (OR = 2.38). After controlling for potential confounders, noncompliance with three or more of these rest break criteria related to risk of depressive mood (OR = 2.61) and headache (OR = 3.11), and noncompliance related to risk of exhaustion in a dose-response relationship (3.10 ≤ ORs ≤ 3.69).