In this paper, we report the generation of high-intensity picosecond pulses in BIBO at 355 nm by using sum frequency generation (SFG) of fundamental pulses at 1064 nm with their second harmonic. The fundamental input pulses were delivered by an amplified mode-locked Nd:YAG laser, providing 35-ps pulses at 1064 nm with energy up to 1 mJ at a repetition rate of 25 Hz in a 2.5-mm beam diameter (EKSMA PL2140). Several BIBO crystals, grown by top-seeded method and of different lengths, were used for the second and third harmonic generation.