Background: Remnant cholesterol (RC) is becoming an increasingly well-recognized risk factor for cardiometabolic diseases. However, no study has explored the predictive role of RC in new-onset cancer. This study aimed to examine the associations between RC and time-weighted RC with incident cancer in the general population. Methods: This was a retrospective population-based study enrolling patients attending family medicine clinics in Hong Kong between 1st January 2000 and 31st December 2003 with at least three RC measurements during follow-up visits. The primary outcome was new-onset cancer. The secondary outcome was cancer-related mortality. Multivariable Cox regression was used to evaluate associations between baseline RC and time-weighted RC with outcomes. Results: A total of 75,342 adults (39.7% males, mean age: 62.5 years old) were included. During a median follow-up of 16.8 years, 8335 (11.1%) incident cancer and 4349 (5.7%) cancer-related deaths were observed. After adjusting for potential confounders, one mmol/L increased of time-weighted RC was associated with 41% and 62% higher risk of incident cancer (HR, 1.41; 95%CI, 1.26-1.57; p<0.0001) and cancer-related mortality (HR, 1.62; 95%CI, 1.43-1.85; p<0.0001), respectively. However, no significant association between baseline RC with risk of new-onset cancer (HR, 1.04; 95%CI, 0.82-1.31; p=0.768) and cancer-related mortality (HR, 0.85; 95%CI, 0.61-1.17; p=0.315) in the adjusted model. The association between time-weighted RC and incident cancer was significant regardless of age, gender, and remained consistent amongst those with baseline use of most cardiometabolic agents, as well as those complicated with most comorbidities. Conclusions: Higher time-weighted RC was associated with increased risk of new-onset cancer and cancer-related mortality amongst the general population.