Polypharmacy is pervasive amongst elderly patients living with multiple chronic conditions and the prevalence is increasing. The Canadian Institute for Health Information recently reported that 26.5% Canadian seniors were prescribed ten or more different drugs in 2016. A member of our team (S. Dahrouge) has found that number of prescription proved to be the most reliable index of persistent complexity and high cost in patients 65 years or older. There is also an association between number of prescription and potentially inappropriate prescriptions (PIPs). Analyses conducted on 86 practices affiliated with the University of Toronto Practice Based Research Network (UTOPIAN) have found that family physicians look after a mean of 24 older patients prescribed ten or more medications each year. Polypharmacy in the elderly is associated with elevated risks of adverse drug reactions, frailty and falls. It also increases healthcare, drug, and hospitalization costs. While several medications can be problematic, the following four classes of PIPs have been specifically identified by Choosing Wisely Canada and the Canadian Deprescribing Network as targets for wiser uses in elders: proton pump inhibitors (PPIs), sedative hypnotics such as benzodiazepines, antipsychotics for agitation and medications with a higher risk of hypoglycemia such as long-acting sulfonylureas. To improve care for elderly patients living with polypharmacy, we propose SPIDER: a Structured Process Informed by Data, Evidence and Research. Leveraging existing Quality Improvement (QI) capacity and provision of validated EMR data, SPIDER will engage inter-professional practice teams. They will participate in Learning Collaboratives and work with QI Coaches to identify areas of improvement, develop strategies and implement changes to improve care. The study aims to assess whether SPIDER can reduce PIPs in older patients prescribed ten or more medications. Patient experience, provider satisfaction and cost-effectiveness of SPIDER will also be evaluated. The study will first be tested for feasibility in Toronto, Edmonton and Montreal. Findings will then guide a pragmatic cluster RCT in Calgary, Winnipeg, Ottawa, Montreal and Halifax where practices enrolled in the SPIDER intervention will be compared with those in usual care.