"He goes to Dalits house for honeymoon and picnic. Had he married a dalit girl, then his luck could have clicked and he would have become the Prime Minister," Ramdev said at a programme here.
He said unlike Rahul, Narendra Modi and Ramdev have not become "fakir" (single) under compulsion.
"Us bechare ki bhi kismat kharab hai (Rahul is unlucky)", Ramdev said.
"His (Rahul's) mother says that if you marry a foreigner girl, then you cannot become the PM and this boy does not want to marry an Indian girl. His mother wants that first he becomes the PM and then marry a foreigner", he added.
Earlier refuting Congress's allegations that he was campaigning for BJP in his yoga camps, Ramdev claimed his camps were "apolitical".
"My yoga camps are apolitical... We do not appeal for votes in these camps... Airing views through the media is my constitutional right," Ramdev told reporters here.
Ramdev said he would go to Amethi on April 30 and claimed Rahul Gandhi would not be able to win Lok Sabha elections from there this time.
On Priyanka Gandhi, Ramdev said that when it came to her husband's matter she said her family was being humiliated but what was happening when "I was targeted and 1,000 cases were lodged against me".
