In the literature there are not much data available to describe the corrosion behavior of titanium nickel alloys and special stainless steels in acids at high temperature in particular above the boiling point. Therefore a laboratory testing program was performed with two titanium alloys (grade 2 (UNS R50400) and grade 12 (UNS R53400) to obtain corrosion data in formic acid acetic acid phosphoric acid polyphosphoric acid p-toluene sulfonic acid and lactic acid at 200°C. Results were compared to previously published ones obtained on alloy31 (UNS N08031) alloy59 (UNS N06059) and B-2 (UNS N10665)From the results it can be concluded that titanium does not always show better corrosion resistance than Ni-based alloys.Alloy59 was the best choice for formic and acetic acids at temperatures. Both Ti-alloys are resistant in acetic acid. Some slight differences were observed for formic acid where Ti Grade2 is only resistant up to a 20% solution and Grade12 also in concentrated acid. The phosphoric acid is extremely corrosive and none of the investigated materials was resistant. In the diluted acid (5%) only Ti Grade12 is resistant whereas in 1% solution all investigated materials withstand. AlloyB-2 and alloy59 showed the best behaviour in polyphosphoric acid. In 30% concentrated p-toluene sulfonic acid at 200°C all alloys tested were unsuitable. In very diluted acid (0.1%) both Ti-alloys behaved well. In lactic acid at 180°C increased corrosion underneath deposits was detected; the best performance was observed for alloy59 and Ti Grade2.