The article discusses the diagnosis of ischemic heart pain and intermittent claudication in field surveys, emphasizing the need for precise definitions and standardized questionnaires to ensure reliable and reproducible results. The study aimed to identify the characteristics of angina pectoris, cardiac infarction, and intermittent claudication that distinguish them from other types of chest and leg pain. The questionnaire used in the study was designed to be straightforward and easy to administer, with clear criteria for diagnosing these conditions. The questionnaire was applied to patients with confirmed cases of angina pectoris, cardiac infarction, and intermittent claudication, as well as to those with non-cardiac chest and leg pain. The results showed that the questionnaire had high specificity and reasonable sensitivity compared to physician diagnoses. However, interpreting patients' answers presented some challenges, particularly in populations with a high prevalence of chronic bronchitis, where the diagnosis of angina pectoris can be more complex. The article also highlights the importance of clear definitions for clinicians and epidemiologists, noting that while clinicians may seek broad definitions to cover a wide range of cases, epidemiologists require more precise definitions to ensure reproducibility and comparability in international studies. The WHO definition of angina pectoris is discussed, and the proposed definitions for ischemic heart pain, possible cardiac infarction, and intermittent claudication are presented. The article concludes by emphasizing the need for agreement on diagnostic criteria and standardized questionnaire techniques to achieve valuable results in international comparisons.The article discusses the diagnosis of ischemic heart pain and intermittent claudication in field surveys, emphasizing the need for precise definitions and standardized questionnaires to ensure reliable and reproducible results. The study aimed to identify the characteristics of angina pectoris, cardiac infarction, and intermittent claudication that distinguish them from other types of chest and leg pain. The questionnaire used in the study was designed to be straightforward and easy to administer, with clear criteria for diagnosing these conditions. The questionnaire was applied to patients with confirmed cases of angina pectoris, cardiac infarction, and intermittent claudication, as well as to those with non-cardiac chest and leg pain. The results showed that the questionnaire had high specificity and reasonable sensitivity compared to physician diagnoses. However, interpreting patients' answers presented some challenges, particularly in populations with a high prevalence of chronic bronchitis, where the diagnosis of angina pectoris can be more complex. The article also highlights the importance of clear definitions for clinicians and epidemiologists, noting that while clinicians may seek broad definitions to cover a wide range of cases, epidemiologists require more precise definitions to ensure reproducibility and comparability in international studies. The WHO definition of angina pectoris is discussed, and the proposed definitions for ischemic heart pain, possible cardiac infarction, and intermittent claudication are presented. The article concludes by emphasizing the need for agreement on diagnostic criteria and standardized questionnaire techniques to achieve valuable results in international comparisons.