In this work we analyze the possibility to generate limited-diffraction electromagnetic pulses in the millimeter-wave range. The propagating and focusing features of such pulses are discussed in terms of spot-lengths over both the propagating and the transverse axes. Starting from a new theoretical framework, we show that, even in the ideal case of non dispersive and infinite radiating apertures, some limitations exist for the spatial confinement of a nondiffracting electromagnetic pulse. However, our results show that practical realizations of such pulses are possible when considering a certain defined spatial region and time interval.