In many low- and middle-income countries, community health workers (CHWs) support multiple aspects of HIV care, including patient education and counseling, adherence support, and re-engaging patients lost to care. In Tanzania, the Community-Based HIV Services program is a nationwide cohort of CHWs supporting HIV care engagement. We enrolled a prospective cohort study of 80 people initiating HIV care at two Tanzanian clinics and conducted baseline and 3-month follow-up assessments to examine the potential influence of CHW support and other factors on patient early self-reported medication adherence, depression, anxiety, attitudes about medication, and HIV stigma. The vast majority of participants reported maintaining strong antiretroviral therapy (ART) adherence during the study and endorsed beliefs that ART is beneficial for them. However, there was high occurrence of likely depression and anxiety disorders in the study sample. Patient contact with CHWs at the clinic was unexpectedly low; fewer than two-thirds of participants were informed about the CHW program and fewer than one-third ever met with a CHW. Among participants who met with a CHW, there was mixed feedback about the helpfulness of the program, and contact with a CHW did not improve medication adherence at 3-month follow-up. Male participants, those with likely depression, and those who lived further from the clinic were significantly more likely to experience adherence challenges. The study findings indicate that CHWs are currently underutilized to provide patient support and may not be producing observable benefits to patients in this setting, representing a missed opportunity to address patient challenges, including depression and anxiety.