Background:Little is known regarding the complex care needs, level of frailty or quality of life ofmulti-morbid older patients. Objectives:The objective of this study was to determine the relationship betweenfrailty, complexity of care and quality of life in multi-morbid older people. Design:Cross-sectional study.Setting: Thirteen primary care practices in the Netherlands. Participants:1,150 multi-morbid older people livingin the community. Measurements:The level of frailty was assessed with the Groningen Frailty Indicator.Complexity of care needs was measured with the Intermed for the Elderly Self-Assessment. Quality of life (QoL)was measured with two items of the RAND-36. Results:In total, 758 out of 1,150 (65.9%) patients were frail,8.3% had complex care needs, and the mean QoL score was 7.1 (standard deviation 1.2). Correlations betweenfrailty and complexity, frailty and QoL, and complexity of care and QoL were 0.67, -0.51 and -0.52 (all p<0.001)respectively. All patients with complex care needs were frail, but, only 12.5% of the frail patients had complexcare needs. Problems at climbing up stairs was associated with higher levels of frailty and complexity of care butwith a lower QoL. Conclusions:Higher levels of frailty and complexity of care are associated with a lower QoLin multi-morbid older people. The results of this study contribute to a better understanding these concepts and arevaluable for the development of tailored interventions for older persons in the future.