This thesis discusses the process of hemostasis, hemostatic disorders and various tests for detection of the disorders of each phase of hemostasis, which is summarized in few chapters. The introduction discusses the roll of each participant in the hemostatic process. Hemostasis is a complex process which includes timely and spatially regulated interactions between the walls of the blood vessels, circulating platelets, membrane associated tissue factor and procoagulant, anticoagulant and fibrinolytic plasma proteins. The aim of this thesis is to list and describe possible steps which every clinician can make to accurately diagnose patients with the occurance of spontaneous bleeding, to help the patient to achieve full recovery. The discussion interprets the three phases of hemostasis in detail, connecting each phase to adequate laboratory diagnostic tests available for the conformation of the suspected disorders, because these tests may be crucial for correctly diagnosing and treating bleeding disorders in domestic animals, small animals respectively. Hence, this thesis describes useful methods of laboratory testing for the detection of the hemostatic disorders, each used for the disorders of one of the three phases of hemostasis, but emphesises the importance of the clinical examination and every clinical practitioner’s experience in recognizing the signs of bleeding disorders, before assessing diagnostic testing. The thesis conclusion summarizes key points of the thesis.