Chronobiology and biometeorology have developed since ancient times of world history (China, Greece, etc.). Different authors have studied the origin and early development of medicine and related sciences in Bulgaria (Apostolov et al 1982, Georgiev 1987, etc.). They have reported that early medical postulates have incorporated the notion of temporal patterns of health and disease and their dependence on the environment. However, these authors have neither emphasized the above relationships nor considered them possible origins of both chronobiology and biometeorology in Bulgaria. The aim was to present evidence for the possible origin and early development of chronobiological and biometeorological perceptions in ancient Bulgaria. Different sources from ancient Bulgarian history were searched and analyzed. Ancient sources from Bulgarian history, relevant to the aim of this study, were reviewed. The evidence on chronobiological and biometeorological understandings in ancient times was obtained from the "Protobulgarian Calendar", Preslav's Rosette, etc. Here, only the most important of Protobulgarian, Thracian and Slavonic sources were presented. It was concluded that chronobiology and biometeorology had also their origin and early development in ancient Bulgarian times.