Background: The Patient-Generated Subjective Global Assessment (PG-SGA) is an instrument to assess malnutrition and its risk factors. Some items of the PG-SGA may be perceived as hard to comprehend or difficult by healthcare professionals. The objective was to evaluate if and how dietitians’ perceptions of comprehensibility and difficulty of the PG-SGA change after a single training in PG-SGA use. Methods: In this prospective evaluation study, Dutch PG-SGA-naïve dietitians completed a questionnaire regarding perceived comprehensibility and difficulty of the PG-SGA before (T0) and after (T1) receiving a single training in instrument use. Perceived comprehensibility and difficulty were operationalized by calculating item and scale indices for comprehensibility (I-CI, S-CI) and difficulty (I-DI, S-DI) at T0 and T1. An item index of 0.78 was considered acceptable, a scale index of 0.80 was considered acceptable, and a scale index of 0.90 was considered excellent. Results: A total of 35 participants completed the questionnaire both at T0 and T1. All item indices related to comprehensibility and difficulty improved, although I-DI for the items regarding food intake and physical exam remained below 0.78. Scale indices for difficulty and comprehensibility of the PG-SGA significantly changed (p<0.001) from not acceptable at T0 (S-CI=0.69; S-DI=0.57), to excellent for comprehensibility (S-CI=0.95) and acceptable for difficulty (S-DI=0.86) at T1. Conclusions: The findings of this study suggest that significant improvement in PG-SGA-naïve dietitians’ perception of comprehensibility and difficulty of the PG-SGA can be achieved quickly by providing a one day training in the use of the PG-SGA.