Objective Unprecedently investigate associations of prognostic‐awareness‐transition patterns with (changes in) depressive symptoms, anxiety symptoms, and quality of life (QOL) during cancer patients' last 6 months. Methods In this secondary analysis study, 334 cancer patients in their last 6 months transitioned between four prognostic‐awareness states (unknown and not wanting to know, unknown but wanting to know, inaccurate awareness, and accurate awareness), thus constituting three transition patterns: maintaining‐accurate‐, gaining‐accurate‐, and maintaining‐inaccurate/unknown prognostic awareness. A multivariate hierarchical linear model evaluated associations of the transition patterns with depressive symptoms, anxiety symptoms, and QOL determined at final assessment and by mean difference between the first and last assessment. Results At the last assessment before death, the gaining‐accurate‐prognostic‐awareness group reported higher levels of depressive symptoms (estimate 95% confidence interval = 1.59 0.35–2.84) and the maintaining‐ and gaining‐accurate‐prognostic‐awareness groups suffered more anxiety symptoms (1.50 0.44–2.56; 1.42 0.13–2.71, respectively) and poorer QOL (−7.07 −12.61 to 1.54; −11.06 −17.76 to −4.35, respectively) than the maintaining‐inaccurate/unknown‐prognostic‐awareness group. Between the first and last assessment, the maintaining‐ and gaining‐accurate‐prognostic‐awareness groups' depressive symptoms (1.59 0.33–2.85; 3.30 1.78–4.82, respectively) and QOL (−5.04 −9.89 to –0.19; −8.86 −14.74 to −2.98, respectively) worsened more than the maintaining‐inaccurate/unknown‐prognostic‐awareness group, and the gaining‐accurate‐prognostic‐awareness group's depressive symptoms increased more than the maintaining‐accurate‐prognostic‐awareness group (1.71 0.42–3.00). Conclusions Unexpectedly, patients who maintained/gained accurate prognostic awareness suffered more depression, anxiety, and poorer QOL at end of life. Promoting accurate prognostic awareness earlier in the terminal‐cancer trajectory should be supplemented with adequate psychological care to alleviate patients' emotional distress and enhance QOL. Trial registration: ClinicalTrials.gov:NCT01912846.