Hi all, I have a data set that I am analyzing and I am trying to do a multiple comparison of means under a glm model. The factors are 2 light treatments and 3 temperature treatments in a complete block design analyzed using a glm. My question is how do I do a multiple comparison of means using the multcomp() package. I have used the following code to look at each treatment separately. germ.glht<-glht(germ.glm,linfct=mcp(Light="Tukey")) but would like to add both temp and light. Is this possible, or is better to simply set up contrasts and adjust? Any help would be appreciated. Wade