The question of the size and the shape of our universe is a very old problem that has received increasing attention over the past few years. The simplest version of cosmological models predicts that the mean density of the universe is very close to the critical density, and that the geometry of the universe is flat. Current results from different cosmological observations confirm this to the percent level accuracy. General Relativity (being a local theory) only determines the local geometry and does not rule out the possibility of having a multiply connected universe with a zero (or small) curvature. To study the shape, or topology, of the Universe, one can use cosmological observations on large scales. In this talk I will briefly review possible ways of constraining the topology of the universe using high resolution, low noise map of the temperature fluctuations in the Cosmic Microwave Background (CMB) radiation and will present current limits on the shape of the Universe.