A 1.5 year old male castrated Yorkshire Terrier presented to the VCA West Los Angeles Behavior Clinic to evaluate is recent anxious behavior. On physical examination, the patient's vital signs were all within normal parameters and blood work from the referring veterinarian was unremarkable. The behavior consultation prompted a diagnosis of separation anxiety. Treatment included intensive behavior modification and administration of Fluoxetine. At the five month follow up, it was reported that the patient was calmer in general, was improved with sit and stay commands, and anxiety was decreased with respect to the owners absence.