The Dof-type transcriptional repressors CYCLING DOF FACTORS (CDFs) directly suppress the expression of CONSTANS (CO), which encodes a key regulator of photoperiodic gene expression, day-length perception and the floral transition in Arabidopsis thaliana. The genes encoding CDF-like (PpDof3 and PpDof4) and CO-like (PpCOL1-PpCOL3) proteins are present in the genome of the moss Physcomitrella patens, although P. patens lacks the genes encoding homologues of FLAVIN-BINDING KELCH REPEAT F-BOX1 (FKF1) and GIGANTEA (GI), which control the stability of CDFs in A. thaliana. In the current study, we investigated whether the functions of PpDof3 and PpDof4 are associated with the expression of PpCOL1-PpCOL3 in P. patens. We found that the diurnal expression patterns of PpDof3 and PpDof4 are similar to those of CDF genes and that like CDF1 from A. thaliana, PpDof3 and PpDof4 function as transcriptional repressors. However, targeted disruptions of PpDof3 and PpDof4 did not affect the expression of PpCOL1-PpCOL3, indicating that the expression of COLs is independent of the functions of PpDof3 and PpDof4 in P. patens.