Abstract: Fluorinated somatostatin analogs are prepared wherein a cyclic hexapeptide contains a secondary amino acid which replaces seven of the ring amino acids of somatostatin and the Lys side chain is monofluorinated in the .gamma. or .delta. positions. The cyclic hexapeptides are easier to synthesize, have a longer duration of activity, and many have a greater level of activity than somatostatin. The compounds have the properties of inhibiting the release of glucagon, growth hormone and insulin. Certain of the compounds also are capable of inhibiting the release of gastric acid secretions. The compounds are particularly useful in the treatment of acromegaly, diabetes, diabetic retinopathy and peptic ulcers. These cyclic hexapeptides are prepared by the solid phase method.