Document and Entity Information	Mar. 19, 2020
Prospectus:
Document Type	497
Document Period End Date	Mar. 19, 2020
Registrant Name	BNY Mellon Municipal Bond Funds, Inc.
Entity Central Index Key	0000075176
Entity Inv Company Type	N-1A
Amendment Flag	false
Document Creation Date	Mar. 19, 2020
Document Effective Date	Mar. 19, 2020
Prospectus Date	Dec. 31, 2019
BNY Mellon Dynamic Value Fund \| Class Y \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DRGYX
BNY Mellon Dynamic Value Fund \| Class I \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DRGVX
BNY Mellon Dynamic Value Fund \| Class C \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DCGVX
BNY Mellon Dynamic Value Fund \| Class A \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DAGVX
BNY Mellon Opportunistic Midcap Value Fund \| Class Y \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DMCYX
BNY Mellon Opportunistic Midcap Value Fund \| Class I \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DVLIX
BNY Mellon Opportunistic Midcap Value Fund \| Class C \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DVLCX
BNY Mellon Opportunistic Midcap Value Fund \| Class A \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DMCVX
BNY Mellon Opportunistic Small Cap Fund \| Class I \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DOPIX
BNY Mellon Opportunistic Small Cap Fund \| Class Y \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DSCYX
BNY Mellon Opportunistic Small Cap Fund \| Investor Shares \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DSCVX
BNY Mellon Structured Midcap Fund \| Class Y \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DPSYX
BNY Mellon Structured Midcap Fund \| Class I \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DPSRX
BNY Mellon Structured Midcap Fund \| Class C \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DPSCX
BNY Mellon Structured Midcap Fund \| Class A \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DPSAX
BNY Mellon Technology Growth Fund \| Class Y \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DTEYX
BNY Mellon Technology Growth Fund \| Class I \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DGVRX
BNY Mellon Technology Growth Fund \| Class C \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DTGCX
BNY Mellon Technology Growth Fund \| Class A \| BNY Mellon Advantage Funds, Inc.
Prospectus:
Trading Symbol	DTGRX
BNY Mellon Floating Rate Income Fund \| Class Y \| BNY Mellon Investment Funds IV, Inc.
Prospectus:
Trading Symbol	DFLYX
BNY Mellon Floating Rate Income Fund \| Class I \| BNY Mellon Investment Funds IV, Inc.
Prospectus:
Trading Symbol	DFLIX
BNY Mellon Floating Rate Income Fund \| Class C \| BNY Mellon Investment Funds IV, Inc.
Prospectus:
Trading Symbol	DFLCX
BNY Mellon Floating Rate Income Fund \| Class A \| BNY Mellon Investment Funds IV, Inc.
Prospectus:
Trading Symbol	DFLAX
BNY Mellon AMT-Free Municipal Bond Fund \| Class Y \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DMUYX
BNY Mellon AMT-Free Municipal Bond Fund \| Class I Shares \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DMBIX
BNY Mellon AMT-Free Municipal Bond Fund \| Class Z \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DRMBX
BNY Mellon AMT-Free Municipal Bond Fund \| Class C \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DMUCX
BNY Mellon AMT-Free Municipal Bond Fund \| Class A \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DMUAX
BNY Mellon High Yield Municipal Bond Fund \| Class Y \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DHYYX
BNY Mellon High Yield Municipal Bond Fund \| Class I Shares \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DYBIX
BNY Mellon High Yield Municipal Bond Fund \| Class C \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DHYCX
BNY Mellon High Yield Municipal Bond Fund \| Class A \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DHYAX
BNY Mellon High Yield Municipal Bond Fund \| Class Z \| Dreyfus Municipal Funds, Inc.
Prospectus:
Trading Symbol	DHMBX

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