Preterm infants are not physiologically or developmentally prepared for life outside the supportive environment of the mother's womb. Their response to stimuli is often immature and disorganized rather than adaptive. The Roy Adaptation Model's theory of an adaptive person may provide a framework for nurses to assess, plan, and evaluate nursing care for fragile preterm infants. The article examines actual and potential stressors of the premature infant; describes commonly observed disorganized, ineffective responses; and proposes a clinical tool (the STRESS tool: signs of stress, touch interventions, reduction of pain, environmental considerations, state, and stability) that nurses can use when caring for medically fragile infants.