There are a total of 98 10-letter words containing 'dem', and the number may vary in different dictionaries. You can specify the dictionary and order.

• academical ₂₁
• academisms ₂₀
• cacodemons ₂₁
• condemners ₁₉
• condemning ₂₂
• condemnors ₁₉
• demagogies ₁₈
• demagoging ₂₁
• demagogued ₂₀
• demagogues ₁₉
• demandable ₂₀
• demandants ₁₇
• demantoids ₁₆
• demarcated ₁₈
• demarcates ₁₇
• demarcator ₁₇
• demeanours ₁₆
• dementedly ₁₉
• demergered ₁₇
• demeriting ₁₇
• demimondes ₁₉
• demissions ₁₅
• demitasses ₁₄
• demiworlds ₁₉
• demobilise ₁₈
• demobilize ₂₇
• democratic ₂₀
• demodectic ₂₁
• demodulate ₁₇
• demography ₂₃
• demoiselle ₁₆
• demolished ₁₈
• demolisher ₁₇
• demolishes ₁₇
• demolition ₁₆
• demonesses ₁₅
• demonetise ₁₅
• demonetize ₂₄
• demoniacal ₁₉
• demonising ₁₈
• demonizing ₂₇
• demonology ₂₀
• demoralise ₁₅
• demoralize ₂₄
• demotivate ₁₈
• demounting ₁₉
• demulcents ₂₀
• demureness ₁₆
• demurrable ₁₉
• demurrages ₁₇
• denudement ₁₈
• endemicity ₂₀
• epidemical ₂₁
• eudemonism ₁₉
• eudemonist ₁₆
• idempotent ₁₈
• oedematous ₁₅
• pademelons ₁₉
• redemanded ₁₇
• redemption ₁₈
• redemptive ₂₁
• redemptory ₁₉
• trademarks ₁₈
• unacademic ₂₂
• vademecums ₂₅
• ademptions ₁₅
• demivoltes ₁₆
• eudemonias ₁₃
• lymphedema ₂₃
• myxoedemas ₂₅
• nondemands ₁₄
• abodements ₁₅
• academists ₁₅
• bridemaids ₁₆
• demagogism ₁₇
• demannings ₁₄
• demarketed ₁₈
• demeasnure ₁₃
• dementated ₁₄
• dementates ₁₃
• demersions ₁₃
• demicanton ₁₅
• demipiques ₂₄
• demirelief ₁₆
• demirepdom ₁₈
• demivegges ₁₈
• demivierge ₁₇
• demologies ₁₄
• demoticist ₁₅
• encodement ₁₅
• eudemonics ₁₅
• misdemeans ₁₅
• myxoedemic ₂₇
• oedematose ₁₃
• pandemonic ₁₇
• precondemn ₁₇
• tandemwise ₁₆
• vindemiate ₁₆

There are 98 10-letter words containing dem in the well-known word game dictionary, 62 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 95 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 65 in the Words with Friends (WWF) dictionary.