Utilization of long-acting antipsychotic injections (depots) shows wide regional variation. In many countries, community psychiatric nurses (CPNs) administer depots but their concerns and attitudes regarding these drugs are seldom considered. We aimed to investigate attitudes and knowledge towards depots in a cross-sectional survey of CPNs in London, and compare them with those of psychiatrists obtained in a previous study. Three subscales of a depot attitude/knowledge questionnaire were used with additional items which referred to aspects of the CPN role. Participants were 70 CPNs who attended an academic meeting. Most CPNs reported that they were involved in treatment decisions (78%) although some CPNs seldom asked their patients about side effects (19%) and felt that they did not have sufficient time for consultations (23%) or training (23%). Several CPNs believed that depots are old fashioned (34%) and stigmatizing (44%). Compared to psychiatrists, CPNs believed more that depots compromised patient autonomy (28%, P = 0.003) and were coercive (42%, P < 0.001). Familiarity with depots and their knowledge of side effects were positively associated with favourable attitudes. CPNs have several strongly endorsed attitudes towards depot medication. Interprofessional group differences also exist which may undermine the treatment process. Training/refresher courses about depots should highlight systematic treatment decision-making and side effect monitoring which, in turn, may improve professionals’ attitudes, knowledge and clinical monitoring of depots.