Planning daily activities, depending on neurophysiological chronotipology, is one of the steps, which should be taken towards the more successful, healthier, high quality life. Aperiod of time within a day during which the individuals of both sexes, different age and profession are intellectually the most optimally efficient, was determined in the paper. The chronotype of a given person was taken into account for that purpose. The research was carried out using a questionnaire. The questioned individuals were divided into four groups: 120 students at the University of Novi Sad, 50 professors at the University of Novi Sad, 50 railway workers and 50 female civil servants employed in administration. The obtained results show the following: the highest percentages of students belong to the morning chronotype. They sleep more than professors do and the optimal time convenient for mental and heavy physical work is from 11 AM to 1 PM. This data should be taken into account while planning student tests. The University professors, both male and female, belong to the morning chronotype. The female professors sleep more than male professors, but are psychologically and physically optimally productive at the same time as the male professors, from 8 AM till 10 AM. In the group of railway workers, the most common are individuals of indifferent chronotype. The highest percentage of women employed in administration belong to the morning chronotype and for their optimal psychological activity they choose the period of time between 8 and 10 AM, as well as the railway workers. According to the opinion of most people that have been questioned, among all of the abovementioned groups, the optimal five-hour working period should begin at 8.30 AM.