A procedure is described for the determination of the short-term and long-term repeatabilities and of the column-to-column and lot-to-lot reproducibilities of the retention and profile characteristics of the peaks obtained with a number of different reversed-phase liquid chromatography (RPLC) C 18-bonded silica columns of several commercial brands. Data characterizing the retention, the steric selectivity, the hydrogen bonding capacity, the hydrophobic interaction selectivity, the column efficiency and the peak asymmetry will be acquired for all the probe compounds. These include 30 neutral, acidic and basic compounds distributed into five groups to be eluted under as many different sets of chromatographic conditions. The data will be obtained using an HP 1100 liquid chromatograph. The compounds and experimental conditions selected were similar to those previously used by different authors for comparison purposes. Careful attention will be paid to minimization of external error contributions by adhering to a strict operational procedure. The precision expected will be high because preliminary results gave standard deviations of around 0.04% for the separation factors, below 0.15% for the retention times and around 1% for the column efficiency in short-term repeatability experiments performed with one column.