Background: In India, 42 million people are suffering from thyroid disorders, out of which hypothyroidism is most common with a prevalence of 5.4%. It is more prevalent among females with the male-female ratio being 1:6. Hypothyroidism is a clinical syndrome resulting from a deficiency of thyroid hormones, which in turn results in a generalized slowing down of metabolic processes. Impaired metabolism can be compared with vitiation of Agni causing Agnimandhya according to Ayurveda. Agnimandhya further hampers the formations of Ahara Rasa and consecutive Dhatus Nirmana, diminishing the metabolism, thereby causing features similar to hypothyroidism. The objective of the Study: To assess the impact of diet & lifestyle on the prevalence of Hypothyroidism in Females. Materials and Methods: It is a cross-sectional survey study. A total of 150 female subjects were selected for the study. With the help of a validated pre-designed and pre-tested questionnaire, the interview was conducted on female subjects diagnosed with Hypothyroidism to assess the impact of diet and lifestyle on the prevalence of Hypothy- roidism in and around Mysuru city. Result: In the survey study, the majority of the hypothyroidism diagnosed subjects followed unhealthy daily regimes and the majority percentage of them practised unwholesome diet, food habits and lifestyle. Diet and lifestyle have a direct influence on the occurrence of hypothyroidism. Conclusion: Hypothyroidism is a metabolic disorder is mainly caused by Agni Mandhya and Rasa Pradoshaja as a result of faulty diet and lifestyle. One should follow Dincharya, Rutucharya and other Ayurveda principles to protect the Agni and thereby prevent Hypothyroidism. The practice of Ahita Ahara Vidhi and Ahita Vihara in the manifestation of Agnimandhya, followed by the development of features of hypothyroidism was substantiated by the result of the survey. Keywords: Hypothyroidism; Diet; Lifestyle; Agnimandhya; Rasa Pradoshaja Vikara.