The paper deals with the analysis of local fuzzy observers for nonlinear plants. The plant is approximated by a TS fuzzy model for which a local linear fuzzy observer is designed. This type of fuzzy observer reconstructs the non-measurable states if the parameters of the locally linearized plant are given. Matched uncertainties in the plant model can be eliminated by an additional nonlinear fuzzy sliding mode observer. Conditions are given under which the combination of the linear and the nonlinear observer lead to a reconstruction of non-measurable states