Introduction. Deep venous thrombosis (DVT) of the leg is a frequent clinical problem that afflicts thousands of people each year. However, little is known about DVT formation after muscle injury. The purpose of this study was to investigate an unusual case of DVT in Polish male patient and assess the risks factors for DVT. Methods. Deep vein thrombosis was diagnosed in a patient by compressions ultrasound with Doppler; atrial fibrillation was verified with electrocardiography. All standard risk factors were also assessed in examination of the medical and social history of patient. Results. The study showed that a recent major trauma, atrial fibrillation, air travel (‘economy class syndrome’), vigorous exercise, and warm water bathing were the probable factors for developing thrombosis in the patient. There was no recanalization of the affected venous segments after 24 days follow-up period. Conclusions. This case study supports the opinion that careful verifying, medical and social history and clinical reasoning in all patients with limb pain are very important in good assessment of thrombosis, as in even young, apparently healthy patients, thromboembolism can occur. Failure of the physician to recognize a vascular injury can elicit many complications and even cause sudden death. It is especially important in rural areas because farm work increases risks of legs injuries.