Pisanello collaborated with Gentile da Fabriano on frescoes in the Doges' Palace in Venice (c. 1415–22) and in St. John Lateran in Rome (after 1427). After Gentile's death, Pisanello probably completed the Roman frescoes, known only through drawings, which show Gentile's great influence over the young Pisanello. Until 1969, when layers of plaster were removed from the walls of the Sala del Pisanello in Mantua's Palazzo Ducale to reveal a series of Pisanello's frescoes depicting scenes of war and chivalry, his only surviving frescoes were thought to have been an Annunciation at the tomb of Niccolò di Brenzoni in San Fermo in Verona (c. 1423–24) and the legend of St. George in the Pellegrini Chapel in San Anastasia, Verona (c. 1433–38). These works are characterized by the curvilinear design, calligraphic draperies, and decorative detail typical of the International Gothic style from which Pisanello never completely freed himself. Even a mature work such as his St. Eustace is encrusted with rich detail that tends to work against spatial clarity. The Madonna with SS. Anthony and George displays a simpler conception. It is dominated by the monumental figures of the two saints and the bust of the Virgin in a mandorla, or almond-shaped aureole.

Pisanello's drawings have been preserved in the Codex Vallardi. This is the only instance in which the drawings of a 15th-century workshop have been preserved virtually intact. They are of unique value, therefore, for the study of the style and techniques of draftsmanship of the period. Pisanello uses a large variety of techniques and materials to produce masterful drawings (some coloured) of animals, plants, costume design, and perspective studies. His drawings of various views of horses are particularly well known. He was one of the first 15th-century artists to draw from life instead of adhering to the medieval tradition of copying the drawings of others. The drawings reveal Pisanello's breadth of interest and his sensitive eye. They combine delicately rendered Early Renaissance naturalism with the beauty of Late Gothic line and are one of his most important contributions to the history of art.