Purpose: Furthermore, the purpose of this study is to compare the student engagement and the learning outcomes in offline and online PBL in the aforementioned course. The COVID-19 pandemic has caused disruption in various sectors, including education. Since it was first announced in mid-March 2020 in Indonesia, teaching and learning activities have been carried out online. In this study, a comparison of the offline (Spring 2019, prior to the pandemic) and online (Spring 2021, during the pandemic) problem-based learning (PBL) method in the sustainable chemical industry course is investigated. Design/methodology/approach: A quantitative analysis was conducted by measuring the students' engagement, course-learning outcomes (CLOs) and student learning outcomes (SLOs). Difference tests of engagement score, CLOs and SLOs were investigated by using the t-test or Mann-Whitney U-test. Furthermore, the perceived students' stressors were measured. Findings: It is found that the students' engagement in offline and online PBL gives similar scores with no significant difference. This is possible because of the PBL structure that demands students to be actively engaged in gaining knowledge, collaboratively working in teams and interacting with other students and lecturers. Although similarly engaged, the CLOs and SLOs of online PBL are significantly lower than offline PBL, except for SLO related to oral and written communication skills and affective aspect. The decrease in CLOs and SLOs could be influenced by students' academic, psychological and health-related stressors during the COVID-19 pandemic time. Originality/value: This study provides a recommendation to apply online PBL during the COVID-19 pandemic time and beyond, although some efforts to improve CLOs and SLOs are needed.