It is uncertain how transfusion knowledge translates to practice. The purpose of the study was to determine if higher scores on a validated Transfusion Camp knowledge assessment test were associated with transfusion order appropriateness. Eligible participants included postgraduate trainees and faculty physicians who had prescribed at least four transfusion orders in the preceding 6 months at two hospitals. Participant data and knowledge were collected using a web-based questionnaire with a validated Transfusion Camp knowledge assessment tool. The most recent 4-10 consecutive transfusion orders per prescriber were independently dually adjudicated for appropriateness based on published criteria. The primary outcome was the correlation between the score on six questions on red blood cells (RBCs), platelets (PLTs), and plasma from the validated test and the percentage order appropriateness. Generalized linear regression was conducted to determine if factors (sex, specialty, participation in Transfusion Camp, previous transfusion education, self-rated knowledge) were associated with appropriate orders. Seventy-four participants (45 trainees, 29 faculty; 31 females, 43 males) completed the test. Median score was 66.7% (interquartile range [IQR]: 50.0, 83.3) for six questions on RBCs, PLTs, and plasma transfusions. Of 546 transfusion orders adjudicated, appropriateness was 90.7% (95% confidence interval [CI]: 87.9%-93.0%). The correlation between prescriber test scores and order appropriateness was very weak (r = -.08). In multivariable analysis, female prescribers (p = .02) and beginner (vs. intermediate) self-rated knowledge (p = .01) were associated with higher transfusion appropriateness. Transfusion knowledge test scores did not correlate with order appropriateness. Factors other than knowledge are key to understanding how to improve appropriate blood use.