In 2012, Connecticut became the 17th medical cannabis state with the signing of HB 5389, An Act Concerning the Palliative Use of Marijuana. HB 5389 provides registered patients with protection from arrest when using or possessing up to a one-month supply of medical cannabis in accordance with the law and allows them to designate caregivers to assist them. Patients and caregivers registered with the Department of Consumer Protection may purchase medical cannabis from state-licensed dispensaries, but no personal cultivation is allowed. Final regulations were issued in 2013, and dispensaries began offering medicine to registered patients in September 2014, with six dispensaries opening throughout the state. 

In 2016, three additional dispensaries were licensed and six new conditions were added to the program.  That year the legislature also passed HB 5450, which allows minors to qualify for the medical cannabis program with some restrictions, creates protections for nurses to administer medical cannabis in health care facilities, and allows dispensaries to provide medical cannabis to medical facilities serving registered medical cannabis patients. A 2018 court case (Noffsinger v. SSC Niantic Operating Co., LLC) reaffirmed employee rights for medical cannabis patients by clarifying that federal law does not preclude enforcement of a Connecticut law that prohibits employers from firing or refusing to hire someone who uses cannabis for medical purposes.

Six new qualifying conditions were added in 2020. This list now includes chronic pain, an essential inclusion to combat opioid abuse. While the state declared cannabis businesses essential during the COVID pandemic, authorized telehealth visits for patient registration renewals, and allowed for curbside pickup during the pandemic, delivery was not authorized for patients.