I would like to present some result concerning packing and Hausdorff dimension for nonconformal repellers in the plane. I'll start from some background material and basic facts which allow to estimate packing dimension in terms of Lapunov exponents and/or the zeros of pressure functions (Bowen-Ruelle formula). Then I'll give a proof of sharp estimate HD(J)>h/λ where h is metric entropy and λ is the smallest Lapunov exponent for a given Gibbs measure μ.