The Fostering Network said the shortage was particularly acute for carers of teenagers, children with disabilities and siblings.
They say that without enough families, children find themselves living a long way from family, school and friends, being split up from brothers and sisters, or being placed with a foster carer who does not have the ideal skills and experience to meet their specific needs.
The charity said the figure matched last year's recruitment target but was a rise on previous years..
Glasgow City Council said there was a need to recruit 75 new foster carers and 25 adopters this year.
Figures from December show there were 1,482 looked after and accommodated children in Glasgow with 1,230 (83%) of those children in foster care.
However, around 150 foster carers are expected to retire in the coming five to 10 years.
Research by the Fostering Network found one in three foster carers has felt pressure to take on children they are not trained to look after.
Two in five carers had looked after children temporarily because the fostering service could not find a suitable long-term home.
The charity would like to see a placement limit introduced in Scotland, similar to the rest of the UK, where families cannot care for more than three unrelated children.
Sara Lurie, director of the Fostering Network Scotland, said: "Children and young people come into care for a wide range of reasons, but all come needing professional, dedicated and compassionate support.
"Fostering can be a challenging job, and when the match between foster family and child is not ideal, it becomes even more difficult. Too many fostering relationships break down as a result; a wider pool of foster carers makes it more likely that fostering services can find the right foster home for each child, first time.
"We urgently need people who believe that they have the right skills and qualities to foster to come forward and make a long lasting positive difference to the life of a child.
"In particular, foster carers are needed to provide homes for teenagers and children with disabilities, and to help sibling groups stay together."
Glasgow City Council's Families for Children now supports 533 fostering households, and 40 carers providing family based respite.