Purpose: Inconsistent results of lipid-lowering medications (LLMs) on improved cancer survival need more investigations. We tested the hypothesis that adherence to the drug would be associated with a lower cancer-specific mortality in a homogeneous population who has ever used the drug. Methods: Utilising data from the Australian Cancer database, linked to the Pharmaceutical Benefits Scheme data and the National Death Index, we identified two separate cohorts of 4519 and 3083 women patients with newly diagnosed endometrial and lung cancer respectively between 2003 and 2013. Adherence to this drug was calculated by proportion of days covered. Cox regression models with time-varying covariates were used to estimate the multivariable-adjusted cause-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of adherence to LLMs, statins, lipophilic and hydrophilic statins, and cancer-specific mortality. Results: Each 10% increase in 1-year adherence to LLMs reduced cancer-specific mortality among women with endometrial cancer (adjusted HR=0.93, 95% CI 0.90–0.96) or lung cancer (adjusted HR=0.95, 95% CI 0.93–0.97). The inverse associations remained unchanged in different subgroup analyses. The reductions in lung cancer mortality were not apparent for women who adhered to lipophilic statins albeit better endometrial cancer survival appeared in the lipophilic statin group and borderline statistical improvement in the hydrophilic statin group. Conclusions: Among LLM users, adherence to this drug is inversely associated with reduced cancer-specific mortality. Together with previous evidence, randomised controlled trials are called for to confirm whether LLMs could be considered as an adjuvant treatment to improve prognosis.