Background: Supportive Care Outpatient Clinics (SCOC) offer comprehensive care and symptom management to patients with advanced cancer (AdCa). Missed appointments (MA) are important source of problems to patient care and clinic operations. But there are no studies on the clinical outcomes of patients who fail to show for consultation. Methods: We determined the frequency of MA, including clinical and demographic data, and reviewed clinic appointment records for 218 consecutive kept (KA) and 218 MA for distinct patients referred to SCOC from January to December 2011. Results: 218/1,352(16%) AdCa who were referred to our SCOC, missed their appointment. Median age was 57 years (interquartile range 49-67). The mean(range) time between referral and appointment was 7.4 days(0-71) for KA vs. 9.1 days(0-89) for MA (p=0.0062). Age, gender, marital status, and cancer types or stages, and reasons for referral to SCOC were not significantly different between MA and KA patients. The reasons for MA were: admission to the hospital 17/218(8%), death 4/218(2%), appointment with primary oncologist 37/218(18%), other appointments 19/218(9%), visits to emergency room(ER) 9/218(9%), and unknown 111/218(54%). MA patients visited more the ER at 2 weeks 16/214(7%) vs. 5/217(2%), p=0.01, and 4 weeks 17/205(8%) vs. 8/217(4%), p=0.06. Median survival for MA patients was 177 days (range:127-215) vs. 253 days (range:192-347) for KA patients (p=0.013). Multivariate analysis showed that MA were associated to the time between referral and scheduled appointment (OR: 1.026/day, p=0.03), referral from targeted therapy services (OR:2.177, p=0.004), living at Texas/Louisiana regions (OR;2.345, p=0.002), having advanced directives (OR:0.154, P<0.0001), and being referred for symptom control(OR:0.024, p=0.0003). Conclusions: AdCa with MA have worse survival and increased ER utilization. We identified AdCa at higher risk for MA who should undergo more aggressive follow up. More research on MA prevention is needed.