Background: WHO, UNODC, and UNAIDS recommend a comprehensive package for prevention, treatment, and care of HIV among people who inject drugs (PWID). We describe the uptake of services and the cost of implementing a comprehensive package for HIV prevention, treatment, and care services in Delhi, India. Methods: A cohort of 3774 PWID were enrolled for a prospective HIV incidence study and provided the comprehensive package: HIV and hepatitis testing and counseling, hepatitis B (HB) vaccination, syndromic management of sexually transmitted infections, clean needles-syringes, condoms, abscess care, and education. Supplementary services comprising tea and snacks, bathing facilities, and medical consultations were also provided. PWID were referred to government services for antiretroviral therapy (ART), TB care, opioid substitution therapy, and drug dependence treatment/rehabilitation. Results: The project spent USD 1,067,629.88 over 36 months of project implementation: 1.7% on capital costs, 3.9% on participant recruitment, 26.7% for project management, 49.9% on provision of services, and 17.8% on supplementary services. Provision of HIV prevention and care services cost the project USD 140.41/PWID/year. 95.3% PWID were tested for HIV. Of the HIV-positive clients, only 17.8% registered for ART services after repeated followup. Reasons for not seeking ART services included not feeling sick, need for multiple visits to the clinic, and long waiting times. 61.8% of the PWID underwent HB testing. Of the 2106 PWID eligible for HB vaccination, 81% initiated the vaccination schedule, but only 29% completed all three doses, despite intensive follow-up by outreach workers. PWID took an average of 8 clean needles-syringes/PWID/year over the project duration, with a mid-project high of 16 needles-syringes/PWID/year. PWID continued to also procure needles from other sources, such as chemists. One hundred five PWID were referred to OST services and 267 for rehabilitation services. Conclusions: A comprehensive HIV prevention, treatment, and care package is challenging to implement. Extensive efforts are needed to ensure the uptake of and retention in services for PWID; peer educators and outreach workers are required on a continuous basis. Services need to be tailored to client needs, considering clinic timing and distance from hotspots. Programs may consider provision of ART services at selected drop-in centers to increase uptake. © The Author(s). 2017.