This study evaluated the correlation between Karnofsky performance status (KPS) and Eastern Cooperative Oncology Group (ECOG) performance status (PS) scores assigned by doctors (MDs), nurses (RNs), radiation therapist (RTT), radiation therapy student (RTS), and patients (PTs) in assessing functional status of patients with cancer. Patients admitted to the general oncology and palliative care wards at our institution participated in the study. Data were gathered from survey forms completed by MDs, RNs, RTT, RTS, and PTs. The Spearman rank correlation coefficient was used to determine the extent of correlation between paired assessments. Thirty-six patients were enrolled in the study, 27 of whom were evaluable (17 men and 10 women), with a mean age of 57.7 years (range, 32-76 years). The correlation for ECOG PS scores were MD/RTS = 0.81; MD/RN = 0.77; MD/RTT = 0.57; MD/PT = 0.64; PT/RN = 0.51; PT/RTT = 0.60; and PT/RTS = 0.64. The correlations for KPS scores were MD/RTS = 0.81; MD/RN = 0.74; MD/RTT = 0.67; MD/PT = 0.70; PT/RN = 0.60; PT/RTT = 0.79; and PT/RTS = 0.60. The findings demonstrate that patients can make valuable and reliable self-assessments as evidenced from the moderate to good degree of correlation of patient-assigned scores with those of health care professionals.