Highlights•Novice nurses participated in smartphone or traditional mindfulness interventions. •The smartphone group showed greater improvements in certain mindfulness skills. •The smartphone group showed marginally better compassion satisfaction and burnout. •Nurses in the smartphone group with pre-intervention posttraumatic stress symptoms, had higher risk for compassion fatigue. Abstract Purpose The current study compares the effects of a traditionally delivered mindfulness (TDM) intervention to a smartphone delivered mindfulness (SDM) intervention, Headspace, an audio-guided mindfulness meditation program, in a group of novice nurses. Design and Methods Novice nurses participating in a pediatric nurse residency program were asked to participate in either a TDM or SDM intervention. Participants (N = 95) completed self-administered pencil and paper questionnaires measuring mindfulness skills, and risk and protective factors at the start of their residency and three months after entering the program. Results Nurses in the SDM group reported significantly more “acting with awareness” and marginally more “non-reactivity to inner experience” skills compared to the TDM group. The smartphone intervention group also showed marginally more compassion satisfaction and marginally less burnout. Additionally, nurses in the SDM group had lower risk for compassion fatigue compared to the TDM group, but only when the nurses had sub-clinical posttraumatic symptoms at the start of the residency training program. Conclusions Smartphone delivered mindfulness interventions may provide more benefits for novice nurses than traditionally delivered mindfulness interventions. However, the smart-phone intervention may be better indicated for nurses without existing symptoms of posttraumatic stress. Practice Implications Mindfulness interventions delivered through smartphone applications show promise in equipping nurses with important coping skills to manage stress. Because of the accessibility of smartphone applications, more nurses can benefit from the intervention as compared to a therapist delivered intervention. However, nurses with existing stress symptoms may require alternate interventions.