Introduction and Aims. Opioids and benzodiazepines (O/BZD) are increasingly involved in drug overdose deaths in the USA. Expanding treatment capacity may reduce these deaths. Knowledge about co-occurring O/BZD admissions compared to opioid admissions (opioid) is needed to plan this expansion. Design and Methods. US treatment admissions to specialty facilities for 2011-2017 were analysed for trends and 2017 for group differences. Due to 1.9 million admissions in 2017, comparisons between O/BZD and opioid admissions were summarised as effect sizes. Additional analysis compared the administratively pre-coded category 'other opiates and synthetics' to other opiates and synthetics/benzodiazepines admissions to control for possible similarity in drug source. Differences within O/BZD admissions by primary drug were explored. Results. Although opioid admissions showed a steady increase over time (25.9% to 38.2%), O/BZD admissions showed increases until decline in 2017 (3.2% to 4.0%). In 2017 no factor reached moderate effect size (≥0.2) in group comparisons or within the O/BZD admissions. Heroin was self-reported in 70% of both O/BZD and opioid admissions. Discussion and Conclusions. No meaningful US national differences on data routinely collected were found for O/BZD compared to opioid admissions including the subgroup with other opiates and synthetics only. Efforts to expand existing opioid treatment in specialty treatments may help reduce opioid and O/BZD deaths. However, the analysis could not address whether changes in treatment would improve outcomes.