BACKGROUND: Asthma and hypertension are common among Emergency Department (ED) patients. Primary care providers are integral in managing these conditions, yet these patients are often in the ED. OBJECTIVE: To determine access to care among ED patients with asthma or hypertension and the association with sociodemographic factors and disease acuity. METHODS: This was a prospective, cross-sectional study of ED patients at an urban county hospital conducted between June 4 and August 31, 2008. Consenting patients were surveyed, and peak flow or blood pressure measured as appropriate. Access to disease treatment was defined as self-reported access to a primary care provider or current prescription for asthma or hypertension, or both. Descriptive statistics and multinomial logistic regression were used to analyze data. RESULTS: There were 2303 patients enrolled; 283 had asthma, 543 had hypertension, and 187 had both. Seventy-one patients (25.1%) with asthma, 151 patients (27.8%) with hypertension, and 19 patients (10.2%) with both had poor access to disease treatment. Seeking ED medical attention was related to having poor access to treatment for patients with both asthma and hypertension. Females with asthma had poor access to treatment. In hypertension patients, good access to treatment was associated with excellent/good health status, housing status, and decreasing age. Poor access to treatment was associated with increasing blood pressure. CONCLUSIONS: Poor access to disease treatment and aspects of socioeconomic status were associated with seeking care in the ED. Changes in access to treatment may affect the number of patients seeking ED care, but not the severity of the presenting illness.