In this paper, we have developed a circuit which gives the output for 4-Logic gates of “AND, NAND, OR, NOR” simultaneously by taking only two inputs “A” and “B”. I used Bipolar Junction Transistors (BJT) to design this circuit. Previously we have each circuit for each logic gate but now in our new circuit, we developed four logic gates in a single circuit. Thus we can decrease the size of the special circuits. Instead of using four IC’s for four logic gates if we use this single IC for all the four logic gates then the space used for the remaining three IC’s can be used for other purposes. This circuit is very easy to design because it has only six Bipolar Junction Transistors (BJT’s).