Japanese kanji (morphograms) have two ways of reading: on -reading (Chinese-style pronunciation) and kun -reading (native Japanese pronunciation). It is known that some Japanese patients with semantic dementia read kanji with on -reading but not with kun -reading. To characterize further reading impairments of patients with semantic dementia, we analyzed data from a total of 9 patients who underwent reading and writing tests of kanji and kana (Japanese phonetic writing) and on - kun reading tests containing two-character kanji words with on - on reading, kun - kun reading, and specific (so-called Jukujikun or irregular kun ) reading. The results showed that on -reading preceding (pronouncing first with on -reading) and kun -reading deletion (inability to recall kun -reading) were observed in nearly all patients. In the on - kun reading test, on -reading (57.6% correct), kun -reading (46.6% correct), and specific-reading (30.0% correct) were more preserved in this decreasing order (phonology-to-semantics gradient), although on -reading and kun -reading did not significantly differ in performance, according to a more rigorous analysis after adjusting for word frequency (and familiarity). Furthermore, on -substitution (changing to on -reading) errors in kun -reading words (27.0%) were more frequent than kun -substitution (changing to kun -reading) errors in on -reading words (4.0%). These results suggest that kun -reading is more predominantly disturbed than on -reading, probably because kun -reading and specific-reading are closely associated with the meaning of words.