ABSTRACT Objectives: to build and validate a data collection instrument for onco-hematological patients undergoing outpatient chemotherapy. Methods: methodological study that aimed to build a scientifically consistent data collection instrument to evaluate hematological patients. There were five stages: identification of empirical indicators, evaluation of empirical indicators by focus group, construction of the instrument, content validation by judges and clinical validation. Built based on the Theory of Basic Human Needs of Horta, adjusted by Garcias and Cubas. Results: the built instrument contains data on patient identification, perception and expectations related to the disease, assessment of psychobiological, psychosocial and psychospiritual needs. It reached 95% CVI, ensuring the instrument’s content validity and Cronbach’s alpha test with a reliability of 0.93. Conclusions: the instrument is a valid technology to assist nurses in data collection and may serve as a tool for onco-hematological nursing care, teaching and research.