Excessive alcohol consumption is associated with increased incidence of several medical conditions, but few nonveteran, population-based studies have assessed levels of alcohol use across medical conditions. To examine associations between medical conditions and alcohol consumption levels in a population-based sample of primary care patients using electronic health record data. This cross-sectional study used separate multinomial logistic regression models to estimate adjusted associations between 26 medical conditions and alcohol consumption levels in a sample of 2 720 231 adult primary care patients screened for unhealthy drinking between January 1, 2014, and December 31, 2017, then only among those reporting alcohol use. The study was conducted at Kaiser Permanente Northern California, a large, integrated health care delivery system that incorporated alcohol screening into its adult primary care workflow. Data were analyzed from June 29, 2018, to February 7, 2020. The main outcome was level of alcohol use, classified as no reported use, low-risk use, exceeding daily limits only, exceeding weekly limits only, or exceeding daily and weekly limits, per National Institute on Alcohol Abuse and Alcoholism guidelines. Other measures included sociodemographic, body mass index, smoking, inpatient and emergency department use, and a dichotomous indicator for the presence of 26 medical conditions in the year prior to the alcohol screening identified using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and ICD-10-CM diagnosis codes. Among the 2 720 231 included patients, 1 439 361 (52.9%) were female, 1 308 659 (48.1%) were white, and 883 276 (32.5%) were aged 18 to 34 years. Patients with any of the conditions (except injury or poisoning) had lower odds of drinking at low-risk and unhealthy levels relative to no reported use compared with those without the condition. Among 861 427 patients reporting alcohol use, patients with diabetes (odds ratio [OR], 1.11; 95% CI, 1.08-1.15), hypertension (OR, 1.11; 95% CI, 1.09-1.13), chronic obstructive pulmonary disease (COPD; OR, 1.16; 95% CI, 1.10-1.22), or injury or poisoning (OR, 1.06; 95% CI, 1.04-1.07) had higher odds of exceeding daily limits only; those with atrial fibrillation (OR, 1.12; 95% CI, 1.06-1.18), cancer (OR, 1.06; 95% CI, 1.03-1.10), COPD (OR, 1.15; 95% CI, 1.09-1.20), or hypertension (OR, 1.37; 95% CI, 1.34-1.40) had higher odds of exceeding weekly limits only; and those with COPD (OR, 1.15; 95% CI, 1.07-1.23), chronic liver disease (OR, 1.42; 95% CI, 1.32-1.53), or hypertension (OR, 1.48; 95% CI, 1.44-1.52) had higher odds of exceeding both daily and weekly limits. Findings suggest that patients with certain medical conditions are more likely to have elevated levels of alcohol use. Health systems and clinicians may want to consider approaches to help targeted patient subgroups limit unhealthy alcohol use and reduce health risks.