Introduction: HIV treatment guidelines recommend initiating antiretroviral therapy (ART) regardless of CD4 cell (CD4) count, barring contraindications or barriers to treatment. An estimated 6% of persons receiving HIV care in 2013 were not prescribed ART. We examined reasons for this gap in the care continuum. Methods: During 2013-2014, we surveyed a probability sample of HIV care providers, of whom 1234 returned surveys (64.0% adjusted response rate). We estimated percentages of providers who followed guidelines and their characteristics, and who deferred ART prescribing for any reason. Results: Barring contraindications, 71.2% of providers initiated ART regardless of CD4 count. Providers less likely to initiate had caseloads200 patients [adjusted prevalence ratios (aPR) 0.69, 95% confidence interval (CI): 0.47 to 1.02, P = 0.03], practiced at non-Ryan White HIV/AIDS Program-funded facilities (aPR 0.85, 95% CI: 0.74 to 0.98, P = 0.02), or reported pharmaceutical assistance programs provided insufficient medication to meet patients' needs (aPR 0.79, 95% CI: 0.65 to 0.98, P = 0.02). In all, 17.0% never deferred prescribing ART, 69.6% deferred for 1%-10% of patients, and 13.3% deferred for >10%. Among providers who had deferred ART, 59.4% cited patient refusal as a reason in >50% of cases, 31.1% reported adherence concerns because of mental health disorders or substance abuse, and 21.4% reported adherence concerns because of social problems, eg, homelessness, as factors in >50% of cases when deferring ART. Conclusions: An estimated 29% of HIV care providers had not adopted recommendations to initiate ART regardless of CD4 count, barring contraindications, or barriers to treatment. Low-volume providers and those at non-Ryan White HIV/AIDS Programfunded facilities were less likely to follow this guideline. Among all providers, leading reasons for deferring ART included patient refusal and adherence concerns.