Scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) have been used to examine the structure of ordered adlayers of Ca on TiO2(110)-1 x 1 formed by metal vapor deposition. A comparison is made with structures formed by segregation of Ca from the bulk, with similar structures being found for the two preparation methods below a monolayer coverage. At low coverages, rows of width similar to0.6-0.9 nm develop in the [1 (1) over bar0] and [001] azimuths. At coverages equivalent to a single calcium layer, a c(6 x 2) overlayer is formed. At coverages above a single layer, a disordered structure develops and a LEED pattern with ((2)(-0.1) (0)(1)) symmetry is observed.