Abstract: Methods for the early detection of gas kicks in marine risers (10) include monitoring a downhole absolute pressure and a downhole differential pressure of a riser section (11) positioned just above the blowout preventer (18). The absolute pressure is used to calculate an average density of mud or mud/gas mixture in the entire riser (10). The differential pressure across the riser section (11) is used to calculate an average density of mud or mud/gas mixture in riser section (11). An unfavorable comparison between the calculated density for the mud or mud/gas mixture in the riser section (11) and the calculated density for the mud or mud/gas mixture in the entire riser (10) is used to detect the onset of a gas kick and to alert the operator. Alternatively, the measured differential pressure across the riser section (11) can be compared with an expected downhole differential pressure. Unfavorable comparisons of the measured and expected differential pressures indicate the onset of a gas kick.