In this thesis we deal with consumer’s choice. We describe the consumer’s choice using object preferences. In the first chapter, we describe consumer’s choice using preference relation, from which we define consumer’s utility function. We express the main theorem of the chapter, which explains equivalence between terms of consumer’s choice, preferecne and utility function. In the second chapter we describe how the utility function changes when we introduce uncertainty in decision making. We describe models which differ if the model is based on objective uncertainties i.e. uncertainties in which we know the event occurance, or subjective uncertainties, i.e. uncertainties in which the consumer makes decisions based on his subjective beliefs. In the last chapter, we observe utility function models for the most common use, the use of money maximization. We introduce the therm of risk tolerance, through which we describe the consumer’s utility function and observe how consumer’s decision making is changed based on his risk tolerence i.e. how much risk is the consumer willing to take. In the end, we explain how the utility function can be used in the business insurance.