This paper presents nonlinear models applied to studies in the ergonomics area. In general, these models evaluate the nature of the relationship between a group ofIndependent Variables (IVs) and one Dependent Variable (DV). In this study the interestis on the effect of the variables thermal perception (Pt); noise perception (Pn); age (A);time of service (Ts) on the working ability. The sample was constituted of 60 publicbus drivers. The Chi-Square test was used to verify the signifi cance between the fi nalmodels and the intercept, thus analyzing the relationship between the dependent andindependent variables. The Wald’s test was applied in order to evaluate the consistencyof the parameter estimates of the IVs. A logistic regression model was built includingthe variables Pt , Pn and A as the IVs. Since A has a greater infl uence on the workingability of the driver, another logistic regression model was constructed consideringjust this variable as the IV. It was concluded that when the bus driver’s age increases by one unit, there is a 23.5% chance of his work ability to fall in the range of poor to moderate.