I believe that we life in an infinitely large (isotropic and homogeneous) universe and so everything that is physically possible will exist somewhere and so I actually do believe in alien life.
But if you're asking: "Do you believe that there are other intelligent lifeforms -having our or better technological capabilities- in the observable universe?", then my answer would be: No. I find it very likely that there will be bacteria (or something similar) on millions of planets in the Milky Way alone, but multicellular lifeforms should be very rare and intelligent life even more so. It's also the easiest solution to the question why we haven't found other intelligent life yet: It's just not there (in the observable universe).