Created in response to the popularity of Casper the Friendly Ghost, Timmy's adventures first saw print in February 1956, in Timmy the Timid Ghost #3. (The first two issues of this series might have been Win a Prize, but Charlton's confusing publication practices of the time, combined with little documentation, make the connection problematic.)
In 1985 Timmy the Timid Ghost returned for a brief three issue run. Issues #24-26 (the numbering system was continued from the last publication date) were reprints of previously published stories. This final series ceased publication when Charlton was forced to declare bankruptcy and subsequently went out of business.