We have developed the set of computer programs for different applications in the field of QSAR and drug design: method for the quantitative description of H-bonding that is founded on large databases of thermodynamic parameters and H-bond factors (the program HYBOT). Supplementing this are other programs. HYBOT-PLUS calculates H-bond descriptors, polarizabilities and partial atomic charges. SLIPPER estimates important properties as water solubility and the lipophilicity-pKa profile. Based on structural fragments, MOLDIVS affords a measure for similarities and diversities among a set of compounds. MOLTRA calculates 3D H-bond descriptors. CONFAN estimates similarities among H-bond donors and acceptors. These programs afford new and quantitative descriptors for H-bonding. Combined with two other important terms for interatomic interactions (steric and electrostatic forces) they can be used broadly in Drug Design and QSAR.