Objectives: To explore and describe the subjective experiences and long-term impact of severe sepsis on survivors of severe sepsis and their informal caregivers (e.g., spouse or family member) through qualitative research methods. Design: A qualitative exploratory study using semi-structured interviews with survivors of severe sepsis and their informal caregivers in the United Kingdom and United States. Participants also completed a demographic background form and sites provided medical history details. Transcripts were analyzed using a thematic analysis approach. Setting: Patients were recruited from a large National Health Service hospital in the United Kingdom and a level 1 trauma center hospital in the United States. Caregivers were recruited through eligible patients. Interviews were conducted either face to face in participant's homes or another convenient location or over the telephone. Patients: Patients who were 18 years old or older and had experienced an episode of severe sepsis in the previous 12 months were recruited by clinical staff in each hospital. Caregivers were family members or friends who had provided informal care for the patient after their episode of severe sepsis. Interventions: None. Measurements and Main Results: Thirty-nine interviews were conducted with 22 patients and 17 informal caregivers (of these 28 were conducted face-to-face and 11 by telephone). Five main themes were identified in the qualitative analysis: Awareness and knowledge of severe sepsis; experience of hospitalization, ongoing impact of severe sepsis; impact on caregivers; and support after severe sepsis. Experiences varied depending on the patients' health prior to the severe sepsis, with the worst affected reporting lasting impacts on multiple aspects of their life. Conclusions: The study extends what was understood about severe sepsis from the patients' and caregivers' perspectives from the previous limited literature. Caregivers as well as patients reported enduring impact. The study also identified problems of lack of awareness of diagnosis and understanding of severe sepsis by patients and caregivers and difficulties accessing appropriate healthcare providers and ancillary services after discharge from hospital.