The American philosopher Paul Grice claimed that people are cooperative in conversation because they act as if they assumed that a certain set of regulations is in operation. Grice elevated his idea of people’s cooperation in what he called “The Cooperative Principle”, which consists of four rules or ‘maxims’ which all require you to be cooperative when talking. However, Grice was well aware that people often fail to observe the maxims, and he considered it as evidence for the fact that people actually work according to the Cooperative Principle. For instance, if we get an answer that does not seem appropriate to our question, we automatically look for an alternative interpretation. In other words, the fact that we act according to the Cooperative Principle makes it possible for us to understand underlying messages such as irony, sarcasm and implied meanings. The main purpose of this paper is to investigate the Cooperative Principle and to find out in what way people work according to it. My basic aim is to focus on the situations when the maxims are broken to see how and why this happens. In order to get an overview of these situations, I have studied the dialogues in two TV shows; namely the comedy Friends and the drama E.R.. The results show that all the maxims are broken at some point, but there is a difference in which maxim is broken in each TV show, as well as the reason for it. The maxim of quantity is broken equally often in both TV shows, and it is mostly because too much information is given. The maxim of quality is the maxim broken most frequently in Friends, where the characters often lie or are ironic in order to be comical. Furthermore, the maxim of relation is broken slightly to the same extent in both TV shows. One reason for this is that in most situations, the speaker wants to avoid a delicate subject and therefore changes the topic. Finally, the maxim of manner is also broken equally often, although for different reasons and on different occasions.