OBJECTIVES: To identify descriptors that patients who have different physical conditions use to describe the quality and severity of their pain, and to examine common use across and between conditions. METHODS: Subjects were recruited by web posting and telephone screening.  Those self-reporting active treatment for one of four conditions (Migraine, Low Back Pain (LBP), Osteo-Arthritis (OA), Rheumatoid Arthritis (RA)) were scheduled for in-person interviews using card sort exercises with 54 different pain descriptors to identify those each subject commonly used to describe the pain associated with their condition.  RESULTS: Subjects ranged between 29 and 63 years (mean age of 45).  The majority (71%) was female, 60% were working full or part time, and 51% were Caucasian.  Pain descriptors were divided into three groups based on percent of subject endorsement; 70-100% for high use 45-69% for moderate use, and 18-44% for low use.  Across all four conditions, the most used pain descriptors were SHARP, ACHING, THROBBING, and HURTING.  Moderate use was shown across all conditions for terms like RADIATING, SPREADING, STINGING, and JOLTING.  Lower percentages of study subjects used descriptors with more specific pain characteristics, including temperature (HOT, SEARING, BURNING), neuropathic characteristics (NUMB, PRICKLING) and qualities associated with acute pain (CUTTING, TEARING). Migraine subjects tended to use descriptors like POUNDING (83%), SPLITTING (88%) and PULSATING (77%).  LBP subjects used STABBING (77%), PINCHING (84%), and SHOOTING (74%).  OA and RA patients tended to be more similar with CONSTANT (46%/73%), TENDER (55%/64%) and SORE (72/73%).  Additional descriptors unique to RA included TIGHT (73%) and CRAMPING (64%). CONCLUSIONS: Because descriptors of pain used by patients across these four different conditions showed use of similar language as well as expressions that were unique to their condition, the assessment of condition specific pain should be considered when planning to use pain as a study endpoint.