Disclosed are methods for preparing dried (preferably lyophilized) preparations comprising a population of alphaviruses or alphavirus replicon particles, a sugar or polyol, a surfactant and a salt and preparations made by said methods, both in the dried form but also as liquids prior to drying or after reconstituting dried preparations. These preparations may further comprise a plasticizer and/or a bulking agent. These preparations are readily reconstituted, with little or no loss in infectivity of the viruses or replicon particles.