The conditions in Venus’ upper mesosphere at around 120 km have some similarities to the upper mesosphere of Earth and Mars where ice clouds form. Here we show, using published satellite products and numerical modelling, that the upper mesosphere of Venus is sufficiently cold that both H2O and CO2 can condense to form particles. In fact, we show that there is likely to be a competition between the direct nucleation of particles from the gas phase (homogeneous nucleation) and the nucleation on meteoric smoke particles (MSPs, heterogeneous nucleation). Amorphous solid water particles (ASW) are likely to nucleate first, resulting in clouds of nano-scaled particles at around 120 km globally. The temperatures can then become sufficiently low that CO2 particles can nucleate either on MSPs or on ASW particles (>30% of the time poleward of 60°). Since the main component of the atmosphere is CO2 these particles will grow and sediment on a timescale of 10-20 minutes. Mie calculations show that these Venusian mesospheric clouds (VMCs) should be observable by contemporary satellite instruments, although their short lifetime means that the probability of detection is small. We suggest that VMCs are important for the redistribution of meteoric smoke and may serve as a cold-trap, removing some water vapour from the very upper mesosphere of Venus, through the growth and sedimentation of cloud particles, and possibly reducing the loss of water to space.