Background Previous studies showed that parents of very preterm infants expressed feelings of incompetence and experienced high levels of stress upon the discharge of their infants. We conducted a systematic review of seven studies and observed potential benefits for parental outcomes when using discharge interventions that adopted guided participation (GP). More evidence is needed on the effective doses of discharge interventions underpinned by the principles of GP. Aim To investigate the feasibility and preliminarily estimate the effects on parental competence and stress outcomes of a newly developed, nurse-led, GP discharge program for mothers of very preterm infants. Methods A two-arm randomized controlled trial was conducted in a neonatal intensive care unit (NICU). Mothers of infants with gestational ages of <= 32 weeks who had no congenital malformations and did not need to undergo major surgeries were recruited. All mothers were the primary caregivers to their infants. The intervention group received a nurse-led GP discharge intervention (three structured 30- to 60-min GP sessions and one follow-up phone call). The control group received usual care. The parental outcomes were measured using the Parenting Sense of Competence Scale (C-PSOC) and Perceived Stress Scale (C-PSS) at baseline (T0), on the day of discharge (T1), after the follow-up phone call (within 72 h after discharge) (T2), and 1 month after discharge (T3). The outcomes were analyzed using generalized estimating equations based on intention-to-treat principles. Results Thirty infant-mother dyads were recruited. Greater improvements in the C-PSOC score were observed in the intervention group than in the control group at T1 and T2, although these differences were statistically insignificant. The intervention group exhibited greater improvements than the control group in the C-PSS scores at T1, T2, and T3, although these differences were also not statistically significant. Conclusions The findings suggest that a GP discharge intervention could improve parenting competence and stress among mothers with very preterm infants. The absence of adverse events suggests that the GP discharge intervention could be feasibly implemented in NICU settings. This feasibility study was not powered to determine the effectiveness of the intervention but is anticipated to lay the foundation for a future full-scale study.