Anxiety and frustration are negative emotional states implicated in many of the most common behaviour problems in dogs and cats1. Both can appear as a specific affective state framed in a specific context or as a consistent emotional reaction over time, forming part of the animal's temperament2. In any case that we find, it is crucial to identify, differentiate and understand the motivation and emotions involved in the behaviours to which we have to apply behavioural modification techniques. There are different behaviour modification techniques applicable to behaviour problems related to anxiety and frustration. Based on our knowledge, exercises can be designed to tailor to each situation and particular animal. A series of clinical cases will illustrate some useful techniques and exercises will be presented with , for the treatment of problems such as aggression towards the family, disorders related to separation or compulsive behaviours. References: 1. Lindsay, SR, (2001). Handbook of Applied Dog Behavior and Training Volume Two: Etiology and Assessment of Behavior Problems. Iowa State University Press, Ames, IA. 2. McPeake KJ, Collins LM, Zulch H and Mills DS (2019). The Canine Frustration Questionnaire—Development of a New Psychometric Tool for Measuring Frustration in Domestic Dogs (Canis familiaris). Front. Vet. Sci. 6:152. doi: 10.3389/fvets.2019.00152.