The Prophet Muhammad laid down principles which clearly forbade any form of visitation of fortune tellers. Safiyyah related from some of the Prophet’s wives that he said: “The Salah (Prayer) of whoever approaches a fortuneteller and asks him (the fotuneteller) anything, will not be accepted for 40 days and nights.” 
The punishment in this hadith is for simply approaching a fortuneteller and asking him questions out of curiosity. This prohibition is is further supported by Mu’awiyah ibn al-Hakam as-Salami’s hadith, in which he said: “O Messenger of Allah, verily there are some people among us who visit oracles.” The Prophet replied, “Do not go to them.” 
A variation in narration was:
Mu’awiya b. al-Hakam as-Sulami reported: I said: “Messenger of Allah, there were things we used to do in the pre-Islamic days. We used to visit Kahins,” whereupon he said: “Don’t visit Kahins.” I said: “We used to take omens.” He said: “That is a sort of personal whim of yours, so let it not prevent you (from doing a thing).”
Such a severe punishment has been assigned for only visitation because it is the first step to belief in fortunetelling. If one went there doubtful about its reality, and some of the fortuneteller’s predictions come true, one will surely become a true devotee of the fotuneteller and an ardent believer in fortunetelling.
The individual who approaches a fortuneteller is still obliged to perform his compulsory prayers throughout the 40 day period, even though he gets no reward from it. If he abandons his salah all together, he has committed another major sin. 
Believing in fortunetellers and believing that they have knowledge of the future or unseen is kufr (disbelief). This is because such a belief assigns to creation some of Allah’s divine attributes with regard to the knowledge of the unseen. Consequently, it destroys Tawhid Al-Asma was-Sifat (the Unification of Allah’s Names and Attributes), and represents a form of Shirk (the gravest of sins), in this aspect of Tawhid.
Abu Hurayrah and Al-Hasan reported from the Prophet that he said, “Whosoever approaches a fortuneteller and believes in what he says, has believed in what was revealed to Muhammad.” 
Some activities that have become so common these days that fall under the category of fortunetelling are:
- reading/watching/listening to fortuneteller predictions
- buying and reading books on astrology and zodiac signs in magazines
- fortune cookies
For any person to predict anything, as in the case of weather forecasters and doctors of pregnant weomen, they should take care to add the phrase insha’Allah (if Allah so wishes), as their statements of prediction are only estimations based on statistical information.
And Allah alone knows best.
 Sahih Muslim (Eng. Trans.), p. 1211, no. 5540
 Sahih Muslim (Eng. Trans.), p. 1209, no. 5532
 Philips, B. The Fundamentals of Tawheed. p. 102
 Collected by Ahmad, Sunan Abu Dawud (Eng. Trans.), vol. 3, p. 1095, no. 3895