We explored doctoral students' writing profiles using a person-centred approach. We also studied differences between profiles in terms of experienced well-being and perceptions of the learning environment. The participants of our study (n = 664) were PhD students from three faculties at the University of Helsinki, Finland. The "Writing Process Questionnaire" (Lonka et al. "Journal of Writing Research," 5(3), 245-269 2014) was used to measure writing conceptions and problematic writing. Well-being was measured by MED NORD, adapted to the doctoral context (Lonka et al. "Medical Teacher," 30, 72-79 2008; Stubb et al. "Studies in Continuing Education," 33(1), 33-50 2011), and "Perceptions of the learning environment," using specific items from Dahlin et al. "Medical Education," 39, 594-604 (2005). PhD students with similar patterns of writing variables were identified through latent profile analysis (LPA). We conducted one-way ANOVAs to examine group differences with respect to well-being and perceptions of learning environment. We identified three writing profiles: "Growth-Transforming" (51%), "Ambivalent" (40%), and "Fixed-Blocking" (9%) groups. The "Fixed-Blocking group" reported a lack of interest the most often and also reported receiving the least feedback. The "Growth-Transforming group" was the most and the "Fixed-Blocking group" the least satisfied with their studies. It appeared that epistemic beliefs related to research writing were most decisive in differentiation among PhD students. Blocks were related to beliefs in innate ability. We concluded that although problems in writing are quite common, epistemic beliefs may be even more decisive in terms of successful research writing.