Pericardial effusion (PE) is an abnormal accumulation of fluid between epicardium and pericardium and may occur due to tumour masses, infectious agents or can be idiopathic in nature. It is more prevalent in large male dog breeds with higher predisposition of Golden retrievers. There are number of modalities that can be useful in diagnosing the pericardial effusion, however, each in one way or other the lack potential for confirmatory diagnosis and thus multiple diagnostic modalities are employed. Radiographic features that are evident in PE include the increase in cardiac silhouette and a Globoid/basket ball appearance of heart. On electrocardiography, decrease in QRS complex voltage and presence of electrical alternans are the usual findings observed. Echocardiography aids in the detection, localization and quantification of pericardial effusion in dogs and is the most sensitive method available for detection of pericardial effusion in dogs. Although, these techniques enable us to diagnose the condition, however, They may not be sufficient enough to arrive at the aetiology of PE. The present review covers the role of radiography, electrocardiography and echocardiography in the diagnosis of pericardial effusion.