Objective Psychogenic non-epileptic seizures (PNES), a common phenomenon in neurological settings, are regarded as a paroxysmal type of functional neurological disorder (FND). In a substantial proportion, PNES are disabling with poor long-term outcomes and high economic costs. Despite the clinical and financial consequences of PNES, there is still a lack of controlled clinical trials on the treatment of this challenging disorder. The study aims to evaluate the feasibility and collect first evidence of the efficacy of a group based-intervention in PNES-patients. Methods A pilot randomized controlled feasibility study with a parallel-group design was performed in adult outpatients with PNES to evaluate a new body-focused group therapy (CORDIS) versus guided self-help groups. Self-assessment of dissociation (Dissociation Experience Scale—DES-20) and seizure severity (Liverpool Seizure Severity Scale—LSSS) were assessed two weeks before and two weeks after the treatment intervention and also six months after treatment as primary outcome parameters. Results A total of 53 patients were recruited from a specialized outpatient clinic, and out of those, 29 patients completed either the body-focused group therapy program (n = 15) or a guided self-help group (SHG) therapy (n = 14). When analyzing the ITT sample (n = 22 CORDIS group, n = 20 SHG), both groups showed an effect on seizure severity and level of dissociation. In the per protocol sample (n = 13 CORDIS group, n = 12 SHG), CORDIS was superior to the self-help group for reducing seizure severity 6 months after the treatment. Significance CORDIS is a newly developed body-focused group therapy program for adults with PNES. Further studies should include a multicentric design with a higher number of participants.