We study the distribution of finite clusters in slightly supercritical (𝑝 ↓ 𝑝 𝑐 ) Bernoulli bond percolation on transitive non-amenable graphs, proving in particular that if 𝐺 is a transitive non-amenable graph satisfying the 𝐿 2 boundedness condition (𝑝 𝑐 < 𝑝 2→2 ) and 𝐾 denotes the cluster of the origin and then there exists 𝛿 > 0 such that if 𝑝 ∈ (𝑝 𝑐 − 𝛿, 𝑝 𝑐 + 𝛿), thenandfor every 𝑛, 𝑟 ⩾ 1, where all implicit constants depend only on 𝐺. We deduce in particular that the critical exponents 𝛾 ′ and Δ ′ describing the rate of growth of the moments of a finite cluster as 𝑝 ↓ 𝑝 𝑐 take their meanfield values of 1 and 2, respectively. These results apply in particular to Cayley graphs of non-elementary hyperbolic groups, to products with trees, and to transitive graphs of spectral radius 𝜌 < 1∕2. In particular, every finitely generated non-amenable group has a Cayley graph to which these results apply. They are new for graphs that are not trees. The corresponding facts are yet