The line was intended for babies who are too young to play with regular Lego Duplo bricks (1–5 years).

The range has expanded to include sets among others with figures, animals, trains, toys making sound, baby walkers, general baby toys and products made of textile.

The Primo name was dropped after 1999 because it was feared to have a negative association with the word "preemie", which is a term that refers to medically fragile babies born before 36 weeks gestation.

Several new sets were launched and the line got a teddy bear logo instead of the yellow elephant.

The elephant that was used as the logo of the Primo brand, was used in blue for the Lego Quatro line from 2004.