We investigate the stability of a Sequential Monte Carlo (SMC) method applied to the problem of sampling from a target distribution on R d for large d. It is well known [9,14,56] that using a single importance sampling step one produces an approximation for the target that deteriorates as the dimension d increases, unless the number of Monte Carlo samples N increases at an exponential rate in d. We show that this degeneracy can be avoided by introducing a sequence of artificial targets, starting from a 'simple' density and moving to the one of interest, using an SMC method to sample from the sequence (see e.g. [20,27,38,48]). Using this class of SMC methods with a fixed number of samples, one can produce an approximation for which the effective sample size (ESS) converges to a random variable εN as d → ∞ with 1 < εN < N . The convergence is achieved with a computational cost proportional to N d 2 . If εN ≪ N , we can raise its value by introducing a number of resampling steps, say m (where m is independent of d). In this case, ESS converges to a random variable εN,m as d → ∞ and limm→∞ εN,m = N . Also, we show that the Monte Carlo error for estimating a fixed dimensional marginal expectation is of order 1 √ N uniformly in d. The results imply that, in high dimensions, SMC algorithms can efficiently control the variability of the importance sampling weights and estimate fixed dimensional marginals at a cost which is less than exponential in d and indicate that, in high dimensions, resampling leads to a reduction in the Monte Carlo error and increase in the ESS.