The diagnosis of canine viral infections frequently requires the correlation of clinical, hematologic, pathologic, and laboratory findings. When laboratory diagnostics are utilized, appropriate specimens must be collected. In addition, correct timing of specimen collection and the proper handling and transport of these specimens are essential. Whenever possible, the practitioner should not rely on any one laboratory procedure for making a diagnosis; rather, a combination of techniques should be used. Submission of tissue for histopathology, virus isolation, and antigen detection techniques (FAT), serum for serologic analysis, and feces whenever enteric infections are investigated will maximize the chances of making a successful diagnosis.