In this master´s thesis we research how colour influences the efficiency of the logo and which of the used colours in the logo is the most efficient for the presentation of the selected activity. The efficiency of the colour means, that the respondents recognize it as the most preferable. Our main motive was to prove the influence of colour on the efficiency of the logo, on it`s better connectivity, visibility and positive association with the activity which is presented by the logo. The logo is composed of different elements. And one of them is colour. We were searching for a way, how to determine the factors, which influence subconscious decisions in graphic design. With the analysis of sources of other authors, we realised that in the designing of a logo we need to take special attention to the colours. Although the colour is not the most important in comparison to other elements of the logo. We went through the theoretical sources in the field of designing an efficient logo and designed a new logo for the customer. We performed the research with the help of the conjoint analysis and an internet program for surveying. The results showed that the colour is not the most important factor amongst the various elements, which influence the decisions of buyers, but has certain effect on that. In the research of the offers of circus art, the respondents were mostly preferring red colour. Among the different kind of performances, they were mostly convinced by open air performances. The time of performance was the longest and the price was most affordable amongst all the others. From the results of the poles we can conclude that on the average the respondents make their consumer decisions based on: firstly, the price and secondary the time, third the content of the performance, and lastly the colour of the logo. We tried the combination of the offer, where we changed the blue colour into the red, and we found out that this improves the preference of respondents. The master thesis opens the possibilities of further study research of the field of the colour influences on the subconscious decisions.