Multiple Trait Derivative Free REstricted Maximum Likelihood (MTDFREML) is a well-known software package that performs analysis of variance components and genetic evaluation by using kinship derived from pedigree. Prior to 2007, the package contained three major subroutines: MTDF-NRM, MTDF-PREP, and MTDF-RUN. The first one builds kinship from pedigree. The rest prepare mixed model equations, run the analysis of variance components, and solve for Best Linear Unbiased Prediction (BLUP). These subroutines and user manual can obtained from the MTDFREML website. We added a subroutine (MTDF-ARM) to incorporate an Arbitrary Relationship Matrix (ARM) for deriving the genetic marker-based kinship relationships (Zhang et al., Journal of Animal Science, 2007). This approach became known as genomic BLUP (gBLUP). The new branch (red arrow) can be download here (MTDF-ARM).