This study investigated the bonding strength development of furfurylated, N-methylolmelamine (NMM) modified and thermally treated birch veneers glued with hot curing phenolformaldehyde (PF) adhesive in different pressing (20, 160 s) and open assembly times (20 s, 10min). For testing, the automated bonding evaluation system ABES was used with 2 N.mm-2applied pressure at 130°C. The bonding strength of both modified and unmodified samplesincreased significantly by prolongation of the pressing time from 20 to 160 s in all cases andfor both open assembly times. A deviation was observed for the samples treated at 220°C andat 20 s open assembly time. With the exception of NMM modified veneers, bonding strengthdid not change significantly by increasing the assembly time in the case of 20 s pressing forboth modified and unmodified samples. At 160 s pressing time, extension of the assembly timedeveloped a better bonding for controls, NMM modified and thermally treated veneers at 180°C.The combination of 10 min assembly time and 160 s pressing time proved as the optimal bondingcondition for controls, NMM modified and thermally treated veneers at 180°C while the highestbonding strength was noted in 20 assembly time and 160 s pressing time for furfurylated veneers.In most of the cases modification affected negatively the bonding performance of the veneers, inparticular for furfurylated and NMM modified samples.