The purpose of this research study was to determine the measurable difference in knowledge attainment among Midwestern undergraduate nursing students who participated in a Second Life virtual respiratory patient nursing care simulation. As avatars, the students developed a nursing student persona, became immersed in the patient-care experience, and collaborated to provide safe patient-care. Social constructivism provided the underpinnings of the virtual simulation research study. Instructional design and simulation principles provided the blueprint for the immersive virtual patient-care simulation and instruction experience. Even though online 3D educational technology has been available for several years, it remains a minimally explored realm for education and medical professionals, especially undergraduate nursing students. Realistic learning scenarios provide learners with opportunities to practice their critical thinking and technical skills in an environment that mimics their workplace setting (Kapp & O'Driscoll, 2010a). The quasi-experimental results demonstrated no significant difference between the pre- and posttest scores, as determined by the t-test at p > .05. The t-test results were supported by the McNemar's statistical test which examined each question on the pre- and posttest and found no change in knowledge gain. For undergraduate nursing students, the 3D online virtual world experience did not contribute to knowledge attainment or loss. Barriers encountered with Second Life during the research study may be attributable to technical and user skill issues due to the steep learning curve. Virtual environments offer alternative simulation opportunities for undergraduate nurses to practice delivery of nursing care to patients, but further research is warranted to validate knowledge attainment during the experience.