In September 1995 the line was introduced under the name as Duplo Primo. The first four sets were #2080, #2082, #2084 and #2086. From 1997 the line was sold under the name Lego Primo and it got a yellow elephant logo. The line was extended with 10 new sets. In 1999 the age indication changed from 6-18 months to 3-36 months.
The name including Primo was dropped after 1999 because it was feared to have a negative association with the word "preemie", or, premature baby. That's why it became Lego Baby from 2000. New sets included sets made of textile. In 2001 the company produced a few sets with Mickey Mouse, in corporation with Walt Disney. In 2002 a big difference appeared, the Lego Baby line had been combined with Lego Duplo line to make 'Lego Explore. Already in 2003 it became clear that the people didn’t recognise Lego Explore as Lego Duplo or Lego Baby. At the beginning of 2004, there came special notices that a set included Duplo elements.
Mid-2004 the big name change was revised. Lego reused Lego Baby again. Several new sets were launched. Also the Lego Baby 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.
Lego Baby was discontinued in 2006